The Spaniard is hoping to add a Premier League title to his trophy collection at some point.
The Dutchman was brought in as the replacement for David Moyes following his disastrous spell in charge and managed to guide the side back into the Champions League at the first time of asking last season.
While that was the remit last year, title challenges are expected at Old Trafford with some predicting one next season, and Mata believes that it is certainly possible under Van Gaal.
“I think he’s good. Obviously he has a lot of experience. He has character,” the Manchester Evening News quotes him as saying.
“He has his philosophy and he follows that philosophy until the end. It’s good for the players.
"The football that he wants us to play is an attractive football and I love that football so I think it’s just a matter of time.”
Premier League title challenge
One philosophy that is unlikely to work is the long ball football, which was a part of United's game for such large periods last season, with fans expecting a more attacking and styling way of winning games.
Van Gaal must also settle on a formation and line-up that both suits him and works, with too much rotation having hampered the side last year.
United were poor at the beginning of last season as the manager chopped and changed both formations and personnel, but they were at their best one a settled side had been established.
If he can work out both of those, then a title challenge seems certain with the likely additions to their squad this summer