Real Madrid's Champions League campaign got off to a terrible start as they were thrashed 3-0 at Bayer Leverkusen.
Jacek Krzynowek, Sena De Souza and Dimitar Berbatov got the goals to stun a shell-shocked Spanish outfit.
French midfielder Zinedine Zidane will be out for about three weeks after dislocating his shoulder in a challenge with Leverkusen defender Roque Junior.
Deportivo la Coruna also endured a disappointing evening, being held to a goalless draw at home by Olympiakos.
Juventus earned an impressive 1-0 win away at Ajax, Pavel Nedved scoring a sublime chip with the outside of his right-foot after a brilliant Juve move.
Roy Makaay's second-half penalty was enough to earn Bayern Munich a 1-0 win over Maccabi Tel Aviv after John Pantsil had fouled Ze Roberto.
Pierre van Hooijdonk scored with an early header to give Fenerbahce a 1-0 win over Sparta Prague in Turkey, although the hosts had Servet Cetin sent off for two bookings.
Roma's match against Dynamo Kiev was abandoned at half-time after referee Anders Frisk was struck by a missile from the crowd following his decision to send off the Italian side's defender Philippe Mexes.
Kiev had taken the lead in the 28th minute, thanks to Goran Gavrancic's sensational 35-yard free-kick.
Manchester United clawed back from 2-0 down in Lyon, thanks to a Ruud van Nistelrooy brace, after Cris and Pierre-Alain Frau had given the hosts a commanding lead.
Liverpool eased to victory at Anfield against last season's beaten finalists Monaco, with Djibril Cisse and Milan Baros finding the target.