Didier Drogba scored twice on his Champions League return to lead Chelsea to a 2-2 draw at Atletico Madrid on Tuesday which sealed the London club's place in the knockout stages with two games to spare.

Drogba, back in European action after a three-match suspension, equalised for Chelsea by heading in a Florent Malouda cross in the 82nd minute after substitute Sergio Aguero had given Atletico the lead.

The Ivory Coast, on his 50th Champions League appearance for the Londoners, striker then raced through the defence to give Chelsea the lead six minutes later, firing in at the second attempt after Asenjo blocked his first effort.

Atletico had not scored in this season's Champions League, including a 4-0 drubbing at Chelsea last month, but went ahead after 66 minutes thanks to a spectacular strike from Aguero.

Aguero, who had replaced the ineffective Florent Sinama Pongolle after 54 minutes, capped a fine performance with a curling free kick to level for Atletico in the final minute.

Porto's 1-0 win at APOEL Nicosia meant the Portuguese team and Group D leaders Chelsea both went through.

Atletico, third with two points from four games, can still claim a spot in the Europa League.

Manchester United reached the Champions League knockout stages after Antonio Valencia struck in stoppage time to give them a 3-3 draw at home to CSKA Moscow in their Group B match on Tuesday.

Trailing 3-1 with six minutes to go, the English champions set up an exciting finale when Paul Scholes headed in a Gary Neville free kick.

A frantic ending ensued and United salvaged a point with a last-gasp deflected strike from Valencia.

The draw put United through to the knockout rounds with two games to spare. They have 10 points from four games, three more than second-placed VfL Wolfsburg who beat Besiktas 3-0. CSKA are third on four points, with Besiktas bottom with one.

"If you want excitement, come to Old Trafford! One of the great pleasures of being a manager here is when you get finishes like that," United manager Alex Ferguson told reporters.

AC Milan striker Alexandre Pato was controversially denied a winning goal in the 1-1 home draw with Real Madrid in Champions League Group C on Tuesday.

Striker Karim Benzema put the dominant Spanish side ahead on 29 minutes when he squeezed a close-range effort under Dida, who had first parried a shot from former Milan playmaker Kaka.

Milan, level at the top with Real on seven points from four games, equalised 10 minutes before the break through Ronaldinho's thumping penalty after Pepe slid in on Gianluca Zambrotta and was harshly adjudged to have handled.

French champions Girondins Bordeaux booked a place in the Champions League knockout round with a 2-0 win at Bayern Munich on Tuesday.

Yoann Gourcuff opened the scoring after 37 minutes and Marouane Chamakh added a late second to guarantee Bordeaux, with 10 points, a top two finish in Group A.

Juventus are second on eight points after a 1-0 win at Maccabi Haifa, leaving Bayern in third spot on four points and facing an uphill battle to qualify.