The Brazil international was superb on the night, setting up Robinho's goal.
"Playing against Barcelona so many times, I saw the importance of wingers in marking them, so I realised how to counter them and that it required sacrifices," the former Real Madrid star told Sky Sport Italia.
"Both Valter Birsa and I did well in playing that tactical role. The Coach knows where I like to play, but at times like this I needed to help out."
"I try to rediscover my best form. As for Milan, I will do whatever it takes for the group. Tonight I needed to help out, work as a full-back and then send passes to Robinho."
It was Kaka's first Champions League appearance of the season and he was invigorated by the San Siro crowd.
"All this affection really helps and is more motivation. I hear them sing every time I step on to the field and there was a really special atmosphere at San Siro tonight. It's the right place for me to play well."
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