Fernandes is the talisman of the Manchester United side and they are depending on him to make sure that he produces a performance at AC Milan tonight in the second leg of their Europa League tie.
The Portuguese is set to return to Italy, where he had a spell between 2012 and 2017, and struggled to impress before returning to Portugal.
He started out his career in Italy with Serie B side Novara and Gattuso saw him up close when he was the coach of the Italian second-tier outfit.
While he conceded that he never anticipated his meteoric rise, the Italian insisted that the mentality he showed from day one was of someone who was destined to be a top player.
Gattuso stressed that Fernandes strived to improve in every training session and his current status is the result of a man who is never satisfied.
He told Italian outlet Tutto Mercato when asked whether he expected Fernandes to reach his current high levels: “So high, maybe I would not have expected it, but the mentality with which he arrived I understood he could do it.
“He was a mental talent and temperamental.
“A boy who from day one wanted to be a professional footballer, and he tried to improve himself in every training session and that’s what he did.
“And today he is a big player at one of the biggest clubs in the world.
“It is the result of someone who is not satisfied and always wants to improve.”
Fernandes made a total of 140 appearances in the top two tiers of Italian football at Novara, Udinese and Sampdoria.
