Ballack returned to the first team squad for the first time since April but had to be content with a place on the substitutes' bench against Liverpool in their quarter-final tie at Stamford Bridge.

The Germany captain insisted that he always believed he would make a return but admitted that he thought his career could be over.

Ballack, speaking to German newspaper Die Zeit, said: "I always believe I would come back. But I have also been incredibly occupied with the injury. I had thousands of questions and none were answered.

"And sometimes I thought 'Man, you are 31, you've had 14 good years as a pro. Maybe it is over'."

Ballack, who found himself criticised by some sections of the home fans during his first year with the Barclays Premier League club, added: "There were moments of real despair at the beginning."