The Red Devils came from a goal down to secure a 2-1 win over Tottenham Hotspur at Wembley on Saturday to book their place in the FA Cup final against Chelsea FC.
Manchester United have fallen short in the Premier League title race to Manchester City, although their form in the top flight has been much improved from recent seaons.
Mourinho is aiming to steer Manchester United to a second-placed finish in his second season in charge at Old Trafford.
And De Gea has paid tribute to Mourinho for the way he has been going about his business at Old Trafford since taking the reigns back in the summer of 2016.
Speaking to Manchester United’s website, De Gea said: “We’ve got a great manager.
“He’s very experienced, he’s won everything there is to win in the game. What he is really good at is transmitting his winning mentality to the group.
“However, at the end of the day, it’s down to ourselves – the players on the field.
“It is us who make the saves, create the chances and score the goals. So, as a group, we’ve got to get that level of consistency and quality throughout the season.”
Manchester United will return to Premier League action on Sunday afternoon when they host Arsenal at Old Trafford.
The Red Devils are aiming to finish as runners-up to Manchester City this season as they then look to try and mount a serious title challenge next term.
Manchester United finished in sixth place in the Premier League and won both the Europa League and League Cup last term.
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