The United midfielder worked with Emery for three years during his time as a Valencia player more than a decade ago and offered an insight into the methods of Emery, who is set to take charge of a record fifth Europa League final.
“I improved a lot with him,” Mata explained.
“I grew as a player and a person. I was quite young, around 21, 22, 23 years old. He improved me as a player and made me feel important in Valencia, playing every single game.
“He's a methodic manager, hard-working, professional, preparing for every single game like a final.