Chelsea reached the knockout round of the Champions League on Tuesday despite conceding an injury-time equalizer in a 2-2 draw with Atletico Madrid.

Chelsea striker Didier Drogba scored two late goals on his return from a three-match ban for the Blues to top Group D with 10 points.

FC Porto also advanced from the group after beating APOEL Nicosia 1-0 to move to nine points. Atletico has two and APOEL one.

"That's the main thing, really," Drogba said of Chelsea's advancement. "It was difficult. We could have played better."

Following a scoreless first half at Vicente Calderon stadium, Atletico substitute Sergio Aguero scored in the 66th minute.

Aguero showed why Chelsea made a reported euro50 million ($74 million) offer for the Argentine in the offseason, being perfectly placed to volley defender John Terry's attempted clearance into the top of the net for the Spanish club's first goal of the competition.

Drogba, playing for the first time in Europe since a foul-mouthed tirade in May, was left unmarked in the 82nd minute to head Florent Malouda's cross home and equalize.

"We had a very good reaction," Chelsea coach Carlo Ancelotti said before praising Drogba. "He is in a good moment. I'm very happy for his behavior and I hope he can continue."

The Ivory Coast striker looked to have won it for Chelsea in the 88th when he slotted in the rebound after goalkeeper Sergio Asenjo had stopped his initial shot.

But Aguero curled a free kick from the edge of the area beyond goalkeeper Petr Cech in the first minute of injury time to level.

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