Mata struck the only goal of the game to send United into the fourth round.
Solskjaer enthused, “How about the run to get through? Speed! First of all, great by Harry - he doesn't just clear it, we tried to play. He doesn't find a pass but he turns and turns and Rashy makes a nuisance of himself, well done Anthony for timing it perfectly.
“I thought he had delayed it too long but [it was] great timing and then what a finish from Juan. We have seen him do that so many times in training. I'm delighted for him. I am delighted by his influence in the team at the moment. He has been absolutely top in the dressing room and around the place.
“When you have players like Sergio, or David it doesn't matter, and Nemanja, Juan, with this group of young players, they're important because they are boys with perspective. They have great experience and have been around the block and been at different clubs. They've seen good times and bad times. They're helping the young lads through this season. They've been absolutely top - all of them."