The Argie striker has put to bed rumours of a move to Real Madrid next season.
He told City's website: "I'm very happy here, because the team has good players and is the best team I've ever played in. I hope that we can go on to win a lot of titles, a lot of trophies.
"I want to score plenty more goals for the fans. All the matches in the Premier League are very difficult, but we will be doing our best to win as many as possible."