Arsenal maintained their 100% record in Group H with a hard-fought 3-1 victory over Partizan Belgrade in Serbia, with their much-criticised goalkeeper Lukasz Fabianski saving a late penalty.
The Gunners claimed their first win in Belgrade thanks to goals from Andrei Arshavin - who later missed a penalty - Marouane Chamakh and Sebastian Squillaci, with Cleo on target for the home side from the spot.
Before the match, a floodlight failure at one end of the ground threatened to force an abandonment - but a late call from the referee allowed the game to kick off on time.
Meanwhile, an injury-ravaged Chelsea side seized control of Group F by strolling past Marseille 2-0 at Stamford Bridge. Despite the absence of Didier Drogba and Frank Lampard, Carlo Ancelotti's men breezed past the French champions with goals from John Terry and Nicolas Anelka.
In his press conference on the eve of the match, boss Carlo Ancelotti urged his players for a reaction following their disappointing loss at Manchester City at the weekend. Terry answered his manager's rallying call by flicking Florent Malouda's corner into the net after seven minutes, before Anelka doubled the lead from the penalty spot after Stephane M'Bia used his hands to stop Michael Essien's cross.
Angel Di Maria hit a late winner for Real Madrid at Auxerre as the Spanish giants jumped to the top of Group G.
Madrid last won the Champions League in 2002 when Zinedine Zidane's famous volley secured victory over Bayer Leverkusen at Hampden Park, Glasgow. They have invested heavily in a mission to reassert themselves in Europe and in the Primera Division, and their summer signing from Benfica came to their rescue in France, firing in well after fellow recent recruit Mesut Ozil found him with a cross to make the breakthrough after 81 minutes and clinch a 1-0 victory.
AC Milan, who beat Auxerre in their opening match, were held 1-1 in Holland by Ajax. Mounir El Hamdaoui put Ajax ahead after 23 minutes after smart work from Luis Suarez, but former Ajax hero Zlatan Ibrahimovic found a leveller for Milan 14 minutes later, after an assist from another one-time favourite of the home crowd, Clarence Seedorf.
Roma recovered from their opening defeat to Bayern Munich in Group E by beating CFR Cluj 2-1. The goals did not come until after the midway point of the second half, with defender Philippe Mexes firing in a crisp shot for the opener after 69 minutes and Marco Borriello striking a superb volleyed second two minutes later. Cluj replied seven minutes later when Ionut Rada headed in, but they could not find an equaliser.
Bayern came from behind to win 2-1 at Basle, who led from the 17th minute thanks to Alexander Frei's elegant curling strike. Bayern levelled with a penalty from Bastian Schweinsteiger in the 56th minute, after Thomas Muller was impeded by Benjamin Huggel, and Schweinsteiger struck again with a minute remaining to pinch the points.
Brazilian striker Ari struck twice as Spartak Moscow stepped up their push for a place in the knock-out stages against a Zilina side who were overrun 3-0.
Ari's compatriot Welliton had been the player Zilina feared the most, after his 16 goals in 17 domestic league appearances for Spartak this year. But former AZ Alkmaar frontman Ari was the player who made the difference between the teams, scoring in each half as the Russians took their points tally to six from two matches, ahead of home and away fixtures with Chelsea.
A double from Luiz Adriano saw Shakhtar Donetsk beat Braga 3-0 away from home, with a Douglas Costa penalty finishing things off for the former UEFA Cup winners.