Fernandes joined United in January and helped guide them into the top four and next season's Champions League.
The 25-year-old scored eight goals and assisted seven times in his 14 Premier League appearances - with four of his goals coming from the penalty spot.
It's something that Tottenham Hotspur boss Mourinho was quick to point out.
He told Portuguese outlet Record per Sport Witness: "Bruno came in, was fit, played very well, improved the United team and also proved to be a great penalty taker, one of the best in the world, because he had about 20 to score."
One of Fernandes' spot kicks came against Spurs in a 1-1 draw last month.
He also looked to have won another penalty after a foul by Eric Dier but VAR intervened and overruled referee Jonathan Moss.
"Fernandes comes from a country that I know well,' Mourinho quipped after the game. "The second one was incredible for me. If VAR goes for simulation, the players could be exposed and given a yellow card."
United themselves were awarded 14 penalties in the league this season which is an all-time high.
Fernandes netted from the spot on Sunday as United sealed their top four spot with a 2-0 victory over Leicester City.
The 25-year-old discussed his goalscoring exploits following the game and stressed he only looks towards the future.
"I think the most important one will be the next.
"I'm always thinking about the next one. I'm happy, all goals are important in different ways.
"It was important for us and for me to score this goal because it gives us the chance to be more calm in the game.
Jesse Lingard sealed victory in stoppage time and it was the England international's first Premier League goal since 2018.
He's been hit with criticism from fans and pundits alike this season, but Fernandes was quick to defend his teammate.
"Of course after when Leicester are behind they try to attack because they need to score twice but we did very well, we defend well and you see in the last minute we never stop the fight and Jesse is doing an amazing job," he told MUTV.
"Of course it's a mistake from the keeper also but if Jesse doesn't go there the goal doesn't come so it's for this we work.
"For me Jesse deserved this goal because of what he works for all week, for all the comments everyone is saying about him and other players because they don't play too much or they don't play good enough.
"I think this is the reason Jesse scored because we're training hard, training hard to help all the team."
Ole Gunnar Solskjaer's side return to action next month when they take on LASK in the second leg of their Europa League last 16 tie.
Featured Image Credit: PA Images & Tottenham Hotspur
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