Protecting a slender advantage, Manchester United will travel to Arsenal on Tuesday. Their ultimate aim is to defend the title they won last year in Moscow. They are two matches from an achievement not emulated since 1990, when the AC Milan of Gullit, Van Basten, Rijkaard, Baresi and Maldini beat Sven Goran Eriksson's Benfica in Vienna, to follow 1989's crushing of Steau Bucharest at the Camp Nou.
Milan's defence of their title was the first since Nottingham Forest, in 1979 and 1980, had repeated Liverpool's twin triumphs of 1977 and 1978, the seventies being a decade in which both Bayern Munich and Ajax won three titles in a row. Previous to that Inter Milan had been consecutive continental champions in 1964 and 1965 while Real Madrid lifted the outsize trophy in every one of its first five years.
Since 1990 all those who have attempted to defend their greatest triumph have eventually come a cropper, the joys of the previous year turning to disappointment. What befell them and at which hurdle did they fall?
AC Milan 1990-91 (Exited in semi-final)
Having been given a bye in the first round, Milan had squeaked past FC Bruges to reach the quarter-finals. They came up against French champions Marseille, in their imperial phase of Jean-Pierre Papin, Abedi Pele and Chris Waddle.
The first leg saw Papin poach an away goal and back in the Stade Vélodrome, Marseille were leading 1-0 through a Waddle goal when, with two minutes to play and the tie ebbing away from the champions, the floodlights failed. Milan director Adriano Galliani took the step of leading the Rossoneri players from the pitch and, when the lights came back on, then refusing to play out the last three minutes in the hope of a replay. UEFA took a dim view of such unsporting chicanery and, after awarding the game 3-0 to Marseille and thus eliminating Milan, chose to ban the former champions European competition for a year.
Red Star Belgrade 1991-92 (Exited in last-eight group stage)
The gloomy final of 1991 ended in a penalty shoot-out after Red Star abandoned the flowing football of previous rounds to stifle Marseille and then beat them on spot-kicks. The following season had seen the arrival of a new group stage for the tournament yet this was the least of Red Star's problems. Yugoslavia was wracked by a bloody civil war of partition, with several of the Red Star players being from a variety of the newly formed countries locked in battle with each other.
In the circumstances, the team mounted an admirable defence of their crown, having to play all their home matches on neutral venues in Hungary and Bulgaria. They reached the group stage set up for the last eight teams left in the competition but had little chance of reaching the final, contested by the winners of two groups, after twin opening defeats to a Gianluca Villa-inspired Sampdoria. Red Star's players soon went their separate ways and a great team was confined to history.
Barcelona 1992-93 (Exited in second round)
Ronald Koeman had realised Catalan dreams at Wembley. Johan Cruyff's "Dream Team" was in the middle of a run of four consecutive Liga titles. Yet the defence of their most awaited crown ended prematurely. A narrow first-round win over Viking Stavanger was followed by the tough assignment of a trip to face CSKA in Moscow. A 1-1 draw seemed to hand Cruyff's team the advantage yet the second leg was catastrophic as the Muscovites won 3-2 in front of a disbelieving Nou Camp.
Olympique Marseille 1993-94 (Banned from competition)
Basile Boli's goal in Munich had made OM the first French club to win a European trophy. Within days of that triumph, the club's name was mud. The testimony of midfielder Jean-Jacques Eydelie that he had bribed three Valenciennes players to "go easy" in a Championnat match a few days before their journey to Germany saw the club stripped of its domestic crown, relegated and banned from defending the European Cup, though not stripped of their title.
AC Milan 1994-95 (Lost in final)
Milan's destruction of Barcelona in the 1994 final may just be the greatest performance in a European final of all time. The scene seemed set for a repeat when they travelled to Vienna to face a very young Ajax side in the following season's final. Despite Ajax twice beating Milan in the group stages, few could see past the Italian giants.
Ajax featured Frank Rijkaard, one of the Dutch trio who been key in 1989 and 1990. His marshalling of the defence kept his old team-mates at bay until coltish sub Patrick Kluivert, just 18, seized on a Rijkaard pass, held off the attempts of the fabled Milan defence to put him off his stride and scored the winner with just five minutes to play.
Ajax 1995-96 (Lost in final)
Coach Louis Van Gaal had restored Ajax to a pinnacle they had not reached since Johan Cruyff quit to play for Barcelona in 1973. Ajax had a chance to emulate their forbears by winning a consecutive title when they reached the final in Rome where they faced Italian opponents once more in Juventus. When Litmanen equalised a Fabrizio Ravanelli goal, an injury-hit Ajax seemed likely to prevail. Yet the game moved into stalemate and extra time failed to separate the sides.
Penalties exposed the callowness of Ajax's team as Edgar Davids missed their first kick. Juve veterans Ferrara, Pessotto and Padovano gave Edwin Van Der Sar little chance in the Ajax goal before full-back Sonny Silooy missed. Vladimir Jugovic confirmed Italian football had its revenge.
Juventus 1996-97 (Lost in final)
Marcello Lippi had been able to add Zinedine Zidane to his midfield as Juventus powered to their second successive final. In Borussia Dortmund they were facing a team granted far fewer riches. Yet for the third successive year, the champions perished at the final hurdle. Ottmar Hitzfeld set Scotsman Paul Lambert on Zidane, and he stuck to him like a limpet.
Lambert temporarily unpeeled himself to set up Karl-Heinz Riedle's opener, the striker soon following up with a header. Juve's expected surge came after Del Piero snapped in a back-heel with 24 minutes to play. Yet the "Old Lady" was left sobbing when 20-year-old sub Lars Ricken, on the pitch for a matter of seconds, conjured a delectable chip to settle matters in Munich.
Borussia Dortmund 1997-98 (Lost in semi-final)
Having been shock winners, Dortmund put up a decent fist of their title defence. The first round group stage was negotiated with ease, nerve was held in a very tight quarter-final with compatriots Bayern Munich, a late goal from Swiss striker Stephane Chapuisat being the first goal of the tie as extra time in the second leg ticked on.
Resurgent Real Madrid, led by Jupp Heynckes, were the semi-final opponents. Dortmund nerves were hardly settled by a 45-minute delay to the first leg after fans ripped down fencing behind the goal. When the game arrived, goals from Fernando Morientes and Christian Karembeu gave Real a telling advantage to take to Westphalia. A second leg 0-0 stalemate ended Dortmund's reign.
Real Madrid 1998-99 (Lost in quarter-final)
Despite the club's first triumph in 22 years, Jupp Heynckes paid for a lack of domestic success and the egos of some of his players with his job. He was succeeded by Guus Hiddink, who had coached PSV to the 1988 title. Yet Hiddink was not the panacea to the Bernabeu problems. Continuing domestic toils were followed by a shock exit from the Champions League.
On reflection, the personnel who ended Real's season were not to be dismissed. Legendary coach Valeri Lobanovsky's Dynamo Kiev team featured Andriy Shevchenko and Sergei Rebrov in attack. Shevchenko grabbed an away goal in the first leg of the quarter final and then followed that with a brace back in the Ukraine. Hiddink did not last much longer at Real.
Manchester United 1999-2000 (Lost in quarter-final)
United's last-ditch win in Barcelona ended 31 years of hurt. A young team had reclaimed the title and looked set to be a contender for years to come. Having negotiated two group stages, as UEFA bloated the tournament, they had the chance to face a team they had not faced since 1968 in the quarter-finals. A 0-0 draw in which Mark Bosnich kept United alive was greeted as a fine result.
At Old Trafford, United set off at typical breakneck pace as they sought to kill off the Spaniards. Captain Roy Keane, for whom the flame burned brightest, having missed the final the previous year through suspension, proved his over-eagerness by scoring an inexplicable own-goal.
Then Raul, with wonderful assistance for his second from Fernando Redondo, put the tie beyond United. They mounted their usual cavalry charge with goals from Beckham and Scholes but it was back to the drawing board. Ferguson consequently abandoned his most attacking instincts for the European game.
Real Madrid 2000-01 (Lost in semi-final)
Vicente Del Bosque had been the architect of Real's latest revival, bringing with him a stability the club has failed to reproduce since. With Luis Figo added to the ranks for a record fee, they were again the dominant force in Spain. After serene progress through the second group stage and a quarter-final win over Galatasaray, they came up against a Bayern Munich side with the bit between its teeth, having been the victims to Manchester United in the 1999 final. They had seen off United in the last eight.
In the first leg of the semi-final, a Giovane Elber strike ended Real's seven-game winning streak in the Bernabeu, leaving them with a considerable task in Germany. Elber scored early to take the tie almost beyond the Spaniards before Figo gave them hope. It was soon over when Jens Jeremies fired in the deciding goal.
Bayern Munich 2001-02 (Lost in quarter-final)
Bayern's superiority over Real Madrid did not last. The last eight of this labyrinthine tournament saw them swiftly reacquainted. Bayern finished top of a second group stage ahead of Manchester United and were rewarded with another trip to the Bernabeu. The first leg in Munich saw an early Geremi goal look like Bayern getting a taste of the medicine they dished out the previous year.
Yet Real, now augmented with Zidane, took their foot off the gas and late strikes from Stefan Effenberg and Claudio Pizarro took matters to Spain on a knife edge. Bayern had been angered by Real's swagger in Germany and looked to have weathered the storm in the second leg until Ivan Helguera grabbed an advantage augmented by sub Guti five minutes from time.
Real Madrid 2002-03 (Lost in semi-final)
Zidane's pearling winner had made it three titles in four years yet Real were still to defend their crown. The addition of Ronaldo (larger model) to their riches made them look even more deadly, especially when he grabbed a hat-trick at Old Trafford in the quarter-finals. Juventus awaited in the semis, seeking vengeance for defeat in the 1998 final. A David Trezeguet poke gave Juve a vital away goal from the first leg before Roberto Carlos gave Real a slender advantage.
In Turin, the style came not from Real but their usually more prosaic opponents, who showed Real how it was done with goals from Trezeguet, Del Piero and Nedved. Zidane signed off with a late strike against his old club but it was little use. Madrid's purple patch was over.
AC Milan 2003-04 (Lost in quarter-final)
An all-Italian final had hardly lifted pulses at Old Trafford before Shevchenko had converted the deciding shoot-out penalty. Milan had added Kaka to a considerable arsenal and looked capable of putting up a considerable defence of their sixth title. After despatching Deportivo La Coruna 4-1 at San Siro in the first leg of the quarter-final, the second leg looked a mere formality.
Yet after the second leg, they were somehow not in the last four. Deportivo, sent out by boss Javier Irueta, attacked in waves from the start. Walter Pandiani created hope with a 5th minute strike. Half an hour later, Juan Carlos Valeron, the gifted playmaker, made it two. It was on. Two minutes before half-time, Alberto Luque gave Depor the advantage in the tie before veteran Fran completed the rout with 15 minutes to play. Milan had collapsed in a fashion that would be echoed a year on in Istanbul.
FC Porto 2004-05 (Lost in second round)
Following UEFA Cup glory with Champions League success the following year was a special achievement for the Portugese side. So special that their manager, Jose Mourinho, was lured by Roman Abramovich's roubles to begin his Chelsea project. To London, he took with him two of his team's defenders in Ricardo Carvalho and Paulo Ferreira. Deco, the attacking fulcrum, also joined Barcelona.
Few expected Porto to defend their crown. Mourinho's succession soon faltered too. Luigi Del Neri lasted only until October, Victor Fernandez was sacked in January. José Couceiro had stepped in to take charge of the team by the time they faced Inter in the last sixteen, having come second in the group stage to who else but Chelsea? There, Inter Milan, despite two goals from Jorge Costa, proved too strong as Porto exited 4-2 on aggregate.
Liverpool 2005-06 (Lost in second round)
They might not even have been in the competition. Not because of the improbability of their comeback in Istanbul but instead because it took an overturning of the rules to get Rafa Benitez's team into the competition, four other English teams already being in the draw. In typical style, the club made a strong case and they were back in, though placed in the very first round of qualifying. Barely seven weeks after returning from Turkey they were taking on the might of Welsh side Total Network Solutions.
After a group stage that saw them reunited with Chelsea, they faced Benfica in their 13th game of the campaign. Tiredness may have been an excuse but a Luisão goal gave the Portugese side a deserved first-leg lead. The return saw Benitez's hopes disappear when a goal from Simão, an erstwhile transfer target, all but ended hopes that were further dashed by a late goal from Fabrizio Miccoli.
Barcelona 2006-07 (Lost in second round)
Victory in Paris restored Barcelona's reputation as the foremost attacking side in Europe. Yet by the following season, Ronaldinho, the undoubted star of the previous last three seasons, had started to fade. As his waistline expanded, the less he was able to weave the magic that had bewitched the world. Lionel Messi was too young to take on the burden and Barca were far less of a force.
Chelsea got the better of them in the group stages and it was another English team that faced them in the second round. The first leg in Spain saw Deco hand them an early lead before Liverpool, knowing they could get at an ailing defence, conjured up an equaliser through lovable rogue Craig Bellamy.
The Welshman celebrated his goal by miming taking a golf shot, in reference to a training ground bust-up that had seen him make use of a golf club in a disagreement with John Arne Riise. The pair's detente was confirmed when Bellamy set up the Norwegian for the second. At Anfield, an Eidur Gudjohnsen goal was not enough for Barca, who exited stage left in disappointment.
AC Milan 2007-08 (Lost in second round)
In beating Liverpool in Athens, AC Milan righted the horrors of Istanbul to claim their seventh European Cup, Paolo Maldini's fifth and Carlo Ancelotti's second as Rossoneri boss. Yet save for Kaka and the addition of Brazilian teenager Pato, this side had a careworn look to it, with time catching up, especially for the defence. A warning shot had been fired by a group stage defeat at Celtic.
Arsenal, a team bursting with youthful vitality, pace and verve, awaited in the second round. The first leg in London ended goalless, but Arsenal had clearly been superior. Milan looked to have escaped lightly yet got their punishment back in Italy. Extra time beckoned as Milan held on for grim life amid Arsenal effervescence before a Cesc Fabregas strike and Emmanuel Adebayor's finish from a Theo Walcott assist delivered just desserts.
Milan were out and with a changing of the guard stillborn, failed to qualify for the competition the following season.
Manchester United would do well to follow these warnings from history.