Celtic surrendered a two-goal lead against Dundee United in the most dramatic of fashion to give Rangers a chink of light in the Clydesdale Bank Premier League title race.
Hoops striker Georgios Samaras scored in the 12th and 57th minutes to give the champions what appeared to be a comfortable lead at Parkhead.
However, United left-back Paul Dixon reduced the deficit on the hour mark with a wonderful free-kick and then Warren Feeney, on for Danny Swanson, grabbed a dramatic equaliser to leave the nerves jangling among the home fans in the closing stages.
Celtic go eight points clear of Rangers but the Ibrox men have the chance to reduce the deficit to five when they take on Inverness tomorrow.
For their part, United are unbeaten in four games against the Old Firm this season and, with a fine second-half performance, cemented their credentials as the third force in Scotland this season.
Despite not having won at Parkhead since 1992, the visitors had reason for some optimism, arriving in Glasgow on the back of a run which had seen them defeated only once in the last 17 matches.
However, that optimism took only 12 minutes to dissipate.
Scott Brown and Samaras had an effort each but it was hardly a whirlwind start from the champions. And there was no danger imminent from Barry Robson's pass into the left-hand side of the United penalty area.
But, for whatever reason, Lee Wilkie dallied and was dispossessed by Brown who squared the ball across the box for Samaras to sidefoot into the corner of the net from 14 yards.
It looked like the perfect platform for Celtic to cruise to yet another home win.
But in the 17th minute United should have equalised when midfielder Scott Robertson found himself with space just inside the box as the Parkhead defence opened up.
Robertson looked to have his shot saved by Celtic keeper Artur Boruc but referee Steve Conroy awarded a goal-kick.
Shunsuke Nakamura and Robson both came close to adding to Celtic's lead as the champions re-asserted themselves.
United, with Jon Daly as their lone striker, struggled to get out of their own half as the Parkhead side probed down both flanks and through the middle but there was precious little goalmouth action before the half-time whistle sounded.
Paul Caddis replaced Mark Wilson at the interval, the former United full-back presumably having picked up an injury in the first half.
United manager Levein resisted the opportunity to make changes and his side certainly had a more positive vibe about them as they set about grabbing the equaliser with impressive enthusiasm.
Celtic's early-game nerves returned and they were guilty of conceding possession far too easily, although Boruc was still well protected by his defence.
But all United's good work appeared to be undone in the 57th minute after defender Sean Dillon was penalised for a foul on Scott McDonald.
When Nakamura's free-kick from the left came in to the six-yard box, Samaras bulleted the ball into the net with his head and the game appeared to be settled.
However, on the hour mark, after Celtic skipper Stephen McManus clattered in to Morgaro Gomis 25 yards from goal, United pulled a goal back.
Dixon stepped up and curled a wonderful free-kick high into the net past the flailing Boruc.
Feeney replaced Danny Swanson immediately afterwards but, seconds later, during a melee inside the United box, Brown's shot was blocked on the line by Dixon.
There was more drama at the other end moments later when Robson was short with his backpass, allowing Feeney to nip in and round Boruc before the United substitute watched his shot cleared off the line by the back-tracking McManus.
Jan Vennegoor of Hesselink replaced Samaras in the 73rd minute but four minutes later, United were level.
After a hotly-contested throw-in was awarded to United, Dixon's long ball was flicked on by Daly to Feeney, who stretched to poke the ball past Boruc from eight yards.
The buoyant visitors were not content with a point and drove forward for the winner.
But, apart from a few moments of excitement, there was to be no more goals.