The 23-year-old surprised with the speed of his adaptation to the Premier League, netting 19 times in United's title-winning campaign.
But the £8m, who prepared for the new term by inspiring Mexico to the Gold Cup, believes even better is yet to come.
"I've been treated wonderfully in Manchester, and I simply need to repay that faith," Chicharito told Fifa.com.
"I had a very good first season and I hope to be able to contribute much more. I think there are good times ahead with this team and I'm very excited about the opportunities ahead in the coming season."