Once a favourite at Manchester United, he is now an inspirational figure in manager Roberto Mancini's ambitious side. A first-half hat-trick against West Brom on Saturday took his tally for the season to 20 goals.
It sets the Argentina striker up nicely for the derby, especially as the gap between the two sides is down to five points with the leaders losing to Wolves. He told ZOO magazine he was not worried about getting plenty of stick at the ground he used to grace.
He said: "I don't care about people booing me at Old Trafford. It doesn't worry me and I'm not worried about going there. The booing happened a lot last year, but I understand. As a supporter, you defend your club and I am on the opposing team now.
"Manchester United fans can never say I didn't give my all during the time I was there. Maybe many supporters still don't understand the reason I left. I am a professional footballer and being booed when I am on the field is a price I have to pay sometimes. But it won't affect me at all. Derby games are always beautiful. I enjoyed them in Argentina and Brazil but, in England, they are extra-special.
"Playing against Manchester United is a big incentive but it's not just because of personal issues for me. It's about the importance of three points. We want to go to Old Trafford and win."