Mata arrived at Old Trafford in a £37.1m switch from Chelsea in January, but has found it difficult to make an impact at the club having been shoehorned into the side on the right wing by David Moyes.
But whilst his arrival was supposed to be the sign of better things to come after a difficult first season in charge for Moyes, yesterday's appalling 3-0 home defeat to rivals Liverpool has piled the pressure on Moyes again, and Mata, writing in his blog today, says that he still believes the tide will turn under the beleaguered United boss.
"The storm will pass and the sun will rise again," said Mata. "I have no doubt."
"Besides, no one said this would be easy, but this is football. It gives you fantastic moments but also very hard times you have to cope with, when you have to show pride and professionalism until the end. And when all this is gone I’m sure I will be a more mature footballer."
Mata, who can't play in this week's crucial Champions League second leg tie with Olympiacos, has appealed for support from the United faithful, with the Red Devils needing to overturn a 2-0 deficit to continue in the tournament.
The Spaniard said: "There are no words to describe your support in the stadium. In games like yesterday it makes me mad not being able to give you what you deserve. I know there is nothing I can say right now, but at least I want you to know how I feel."
It will be of little comfort to United fans, who had to endure their embarrassing defeat to Liverpool, but supporters tend to appreciate their players communicating with the fan base regularly like Mata does.