Michael Ballack says Chelsea teammate Didier Drogba is unstoppable.

Drogba struck twice in last night's 2-2 draw with Atletico Madrid.

And midfielder Ballack said: "It was great to have Didier back in the Champions League and he proved what he can do yet again. He was absolutely fantastic. He is world class and, as he showed with his goals, no defender can afford to lose him in a match right now as he'll score."