Having seen a £37million transfer from Chelsea make him United's record signing, big things are expected of the Spaniard at Old Trafford.
He started to offer a return on that considerable outlay on Tuesday as he helped David Moyes' men condemn rock-bottom Cardiff to a 2-0 defeat.
Mata played a part in the opening goal of the contest and admits he thoroughly enjoyed his first outing as a Red Devil.
He told Sky Sports: "It was amazing, the atmosphere. The most important thing is that we won, we got the three points. This is hopefully the beginning of a good run of results.
"It's been an amazing game for me - I tried my best, my team-mates are very good and the atmosphere has been incredible.
"It's been a while since the last game I played, it was 1st January. Last week I didn't train very much because I was waiting. I am very happy to have played in the line-up and I'm looking forward to playing more.
"When you play alongside players like Robin (van Persie), Chicharito (Javier Hernandez), (Wayne) Rooney, Adnan (Januzaj), they are all very good.
"It's special for me, three points, victory and I'm looking forward to playing at the weekend."
Asked for the stand-out moment in his 85-minute bow, Mata said: "When I went off all of the stands were cheering me and it is something that I will never forget."