Even though he had just two training sessions under his belt, United's club-record £37.1million new boy lasted all but the final seven minutes of Tuesday's 2-0 win over Cardiff.
Mata could even claim a partial assist for Robin van Persie's opener given it was the Spain midfielder who delivered the impressive 50-yard cross-field pass to Patrice Evra that launched the sixth-minute move.
And with United both winning and, at times, looking more convincing than they have done since the turn of the year, Mata has every reason to be satisfied.
"I have felt comfortable at this club from the first minute," said the 25-year-old.
"Time has gone so quickly but the welcome has been amazing.
"The lads are really good and there is a great atmosphere."
And the good news for United is that Mata is acutely aware there is still much more to come from him.
"To be honest I didn't train that much last week because of the transfer," he said. "I know I can improve."
And his efforts will only be enhanced by the return to fitness of Robin van Persie, who had missed 11 games with a thigh problem, and Wayne Rooney, who played only once in 2014 before succumbing to a groin injury.
"Rooney and Robin are two of the best strikers in the world," said Mata.
"It will be amazing to play alongside them.
"I just want to help them, and help the team win matches.
"We need to sustain this feeling.
"I am always positive. If any club can come back and climb the table it is this one.
"It will take time but hopefully we can go back up the table. That is what we have been talking about in the dressing room.
"We will try to win as many games as we can to the end of the season, hopefully all of them."
Mata was also complimentary about the United supporters, who have been given so little to shout about this season.
There was certainly a less foreboding atmosphere around Old Trafford, fuelled in part by the reception for Cardiff manager Ole Gunnar Solskjaer, who is held in such huge affection at United the hosts were still singing his name at the final whistle.
For the uplifting mood to be maintained though, greater consistency is required.
Liverpool laid down a pretty significant marker at Anfield, and the groans from supporters as the result of the Merseyside derby was read out at the final whistle underlined what a tough job United face if they are to claim that precious final Champions League slot, which seems to be the only realistic prize available to them on the domestic front.
Moyes believes there is genuine reason to believe his troops will enjoy a far better end to the campaign than their troubled start.
And though Marouane Fellaini and Michael Carrick sat out the game with wrist and ankle problems respectively, the presence of Rooney and Adnan Januzaj as headline names on a bench packed with international experience gives Moyes justifiable reason for his optimism.
"People would have looked at our bench and said that is more like it," said Moyes.
"We are starting to get players in.
"I need competition and I need players to play well.
"We have not had enough right at the top of their game. Hopefully the competition for places will help make that happen."