Manchester City will face Real Madrid for the first time in a competitive match after being drawn against Jose Mourinho's side in the Champions League group stage Thursday.
City has the toughest group of all in Group D with the Spanish champions Real, Dutch league winners Ajax and German double-winners Borussia Dortmund all dangerous opponents.
Chelsea, the defending European champions, also have a tough-looking task in Group E along with Shakhtar Donetsk, Juventus and Nordsjaelland.
Manchester United and Arsenal have more straightforward groups. The Gunners are in Group B with Schalke, Olympiacos and Montpellier, while Sir Alex Ferguson's United will take on Braga, Galatasaray and CFR Cluj in Group H.
There are a couple of potential interesting matches for Celtic in Group G -- Barcelona is in the group along with Benfica and Spartak Moscow.
The four clubs in each group will play each other home and away with the top two progressing to the knockout stage of the tournament, while the third-placed side goes into the knockout stage of the Europa League.
Real Madrid midfielder Cristiano Ronaldo admitted that Group D was the toughest.
"It is the most difficult group in my opinion and I think that's the same for most people," he said. "But we are champions of Spain and we are ready to compete with everybody."
Manchester City captain Vincent Kompany said his teammates should be philosophical about the draw.
"Looks like we're not going to get any easy games again this year but it is certainly a good group for the fans," he tweeted.
"I'm looking forward already!"
Ferguson told his Manchester United players they cannot afford to make the "stupid errors" they committed in Europe last season after the Reds were handed another relatively easy-looking group.
United are expected to qualify for the knockout stages, but Ferguson is aware that his side was predicted to make Round 2 last year after being given a favorable draw against Benfica, Basel and Otelul Galati, however, and for that reason, he insists his squad cannot afford any slip-ups this time around.
Ferguson, who has bolstered his squad since last season by signing Robin van Persie, is also aware that his team will find it extremely hard to come through the test of playing in a very hostile environment in Turkey when facing Galatasaray.
"We have the experience of playing against Galatasaray in the past and we will always remember the 'Welcome to Hell' banners," Ferguson told the team's website. "So it's always a difficult type of match."
The draw also throws up an interesting subplot in the return of Real coach Mourinho and former Manchester United star Ronaldo to the northwest.
Real Madrid director of football Emilio Butragueno says Mourinho's players will be excited about the prospect of playing in England.
"Playing in England is a great pleasure because the fans are extremely passionate," Butragueno told Sky Sports News. "It's a unique experience so I'm sure they will be excited about it."
Information from Press Association was used in this report.