He played 85 minutes - an impressive duration given his recent lack of match practice with his former club - and afterwards thanked the United fans for the rapturous welcome he received.
Mata told MUTV: "I'm so grateful. From the first minute, from the warm-up they [the fans] have been amazing for me. I will just try to give this confidence back on the pitch.
"It was a very special day for me. My first game - my debut - with a victory. It was perfect. I enjoyed it a lot.
"What I love the most is to play. So these minutes [on the pitch] for me are very important. Now I'm going to train and I'm looking forward to playing at the weekend and trying to do my best for the team."
When asked about his contribution to United's 2-0 win, which was sealed with a goal in each half from Robin van Persie and Ashley Young, Mata said: "I tried to play passes for the wingers or the strikers and in the end we scored twice. The most important thing was we won and I felt comfortable with my team-mates."
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