Mata: AVB wants more attacking Chelsea this season
Mata tied up his transfer from Valencia on Wednesday, and will be available for Saturday's game against Norwich, having already trained with the squad earlier.
The left winger, 23, said: "Valencia were a big club but I have left to join a bigger club and it is all about the opportunity to win trophies. I would love to win a trophy in my first season. If it can be the Premier League then great.
"Villas-Boas said he wanted Chelsea this season to play more attacking football, and that I would be a big part of that. I can play on either flank or even in the middle in between the lines of midfield and attack. I like to keep the ball and use it well, I am an attacking player and I like to set up goals and score them."