AC Milan midfielder Kaka said his side were relieved to be in the last eight of the Champions League after the 1-0 extra-time victory over Celtic.
Kaka said he was worn out after the extra-time win over Celtic
Kaka, who scored the winning goal in the 93rd minute at the San Siro, said: "I'm really happy with the contribution I made to the team.
"It was a difficult game, really difficult and we are worn out.
"Celtic showed lots of maturity and tried to play their game but in the end we scored because we deserved it."