The Spanish playmaker topped the poll for April on the club's official websites and subsequently tweeted a message to the fans who voted for him: "Thanks again! Gracias de nuevo."
Mata was cup tied for the Champions League double-header against Bayern Munich, but he turned in some excellent displays in the Barclays Premier League to win the accolade ahead of fellow nominees Shinji Kagawa and Phil Jones. The 26-year-old scored a superb brace in the Reds’ impressive 4-0 away win over Newcastle United, and needed just 30 minutes as a substitute to repeat the feat against Norwich City in Ryan Giggs’ first game as interim manager.
Speaking to MUTV about the award, Mata said: "I'm happy and very grateful. We had two great games in April - Newcastle away and Norwich at home - so I think that's why I got it.
"Since my first game at Old Trafford, the fans have been amazing with me. The only thing I want is to give them as much as I can on the pitch. We look forward to bringing success back to the supporters. I think it's what they deserve."
Voting for United's Player of the Year - at www.manutd.com/awards - will close at 21:00 BST on Thursday, with the result due to be announced later in the same evening during the club's awards dinner at Old Trafford.