The Spaniard was brought on as a substitute as early as the 19th minute at Old Trafford on Saturday, replacing a beleaguered Eric Bailly as United trailed Newcastle by two goals.
Mata got Uniteds comeback going with a pin-point free kick in the 70th minute before Anthony Martial and Alexis Sanchez completed a dramatic comeback.
We needed something and yesterday [Friday] I was practising free kicks in the training ground. I scored I think three in a row and I left, so I said, I think I have the touch and today exactly it proved, he told Man Utds official website.
The build-up to the game was dominated by reports suggesting Jose Mourinho would be sacked over the weekend with fans at Old Trafford voicing their support for the Portuguese boss even when they were trailing in the first half.
Mata praised the vocal support for pushing the team towards their eventual win but admitted the fans deserved better than from the players especially because of the continuing off-field issues.
Definitely, they pushed us, they helped us, to go more, to try more, to give this 50 minutes more and Im very happy for them. Im very happy for the team, for us, but especially for the fans, he said.
They dont deserve everything that is going on, so they deserve to see a team like today.