Didier Drogba celebrates after the late own goal, which also turned out to be the last action of play in the match.
With time almost up it looked as though the seventh meeting between the teams in the Champions League in the last four seasons was about to end in a 1-0 scoreline for the fourth time.
Instead this match became the first to produce two goals and leave the tie on a knife-edge with Chelsea the slight favourites to advance to the final in Moscow on May 21.
Complete Coverage: UEFA Champions League