Mata struck in yesterday's 1-1 draw at Southampton.
"Today, it was an important goal but not enough to win which is what I wanted," he told MUTV.
"Personally, I'm quite happy because I've played a lot of games, I've scored six goals and gave five assists as well, so I'm happy with my job. But obviously I wanted to win more games, we lost games where we didn't play very well, so I'm not happy with that.
"I'll be pushing next season to score more goals, have more assists and try my best for the club. I'll keep going and fight for the titles. I'm happy with these six months, but I'm looking forward to next season to have a whole year to see how I can perform and how we can be back even stronger."
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