GROUP E
Real Madrid got off the mark in Group E with a Raul-inspired 5-1 thrashing of Dynamo Kiev in The Bernabeu.
Raul and Ruud van Nistelrooy scored twice with Jose Reyes netting too, while Artem Milevsky scored for Kiev, who had Olexandr Shovkovskiy sent off.
Lyon eased to their second victory of the European campaign with a 3-0 win away at Steaua Bucharest.
Brazilian Fred put Gerard Houllier's side ahead, with Tiago and Florent Malouda wrapping it up after the break.
GROUP F
Match report
Manchester United earned their second successive Group F win, with a slender 1-0 victory in Portugal at Benfica.
United were far from at their best but got the three points thanks to striker Louis Saha's immaculate finish.
Match report
Scottish champions Celtic got off the mark after their defeat at Man Utd, winning 1-0 against FC Copenhagen.
Missing Jan Venegoor of Hesselink through injury, Celtic won thanks to a Kenny Miller spot-kick after Shunsuke Nakamura was felled in the box.
GROUP G
In Group G, CSKA Moscow secured their first three-point haul of this season's Champions League campaign by seeing off Hamburg 1-0 in the Dynamo Stadium.
Dudu bagged the only goal of the game just before the hour mark, powering home a header from a left-wing corner.
Hamburg also had Benjamin Lauth sent off for an alleged elbow near the end.
Match report
Arsenal notched their second successive win of the campaign, winning 2-0 at home to FC Porto, with Thierry Henry and Alexander Hleb on the scoresheet.
GROUP H
Italian giants AC Milan dropped their first points of the Champions League campaign, drawing 0-0 away at Lille.
Milan dominated before the break with Kaka going close several times, but the visitors improved and Dida made some fine saves to earn Milan a draw.
In the group's other game, AEK Athens and Anderlecht shared the spoils after a 1-1 draw in Greece.
The Belgian side took the lead when Nicolas Frutos struck, but Julio Cesar levelled the score three minutes later.