The Spanish playmaker scored the only goal of the game with a delightful second-half dink over John Ruddy, to book United a fourth round place.
Mata, 31, hasn’t been a guaranteed first choice this term, but was man of the match after a standout display – having also impressed in the 4-0 thrashing of Norwich at the weekend.
The former Chelsea man remains valued by Ole Gunnar Solskjaer and it was noticeable during the first half that when the Norwegian looked to make a change, he handed a note to Mata, for him to explain elsewhere.
Asked post-game on BT Sport what the note said Mata joked that his boss was asking him to buy some bread and milk.
But Solskjaer offered a far more realistic alternative, explaining how Wolves decision to start Adama Traore on the left wing rather than his more regular home on the right, made up his mind for Dan James to swap flanks.
“It was just a spell there that we struggled a little bit, I felt,” Solskjaer said. “The players were just playing more off the cuff than they should have been doing.
“When they swapped Traore we just swapped Dan over for a little while, and it worked. Dan was straight through on goal two seconds after.”
Wales winger James made a blistering start to life at United following his summer arrival from Swansea, scoring three goals in his opening four Premier League matches.
But he hasn’t score since, and spurned a one-on-one opportunity in the first half, being denied by Wolves stand-in stopper Ruddy.
Mata showed more composure when he went clean through and secured victory, and Solskjaer believed that the 22 year-old must learn from the elder Spaniard.
“It’s not often you create that many clear opportunities that we did with Dan,” added Solskjaer.
“There were] some great runs in behind from him and he needs to learn from Juan. That composure, an absolute beauty of a goal.
“Great timing with his run as well, we were a little bit scared he was offside, but no. Sometimes the brain is quicker than the feet.”