The Crimson Devils claimed back-to-back Premier League victories and condemned Watford to their first defeat of the season with a 2-1 win at Vicarage Highway.
United led 2-Zero at half-time due to first-half objectives from Romelu Lukaku and Chris Smalling.
Watford halved the deficit halfway by the second half by Andre Grey and pushed for an equaliser in the direction of the top of the match as Nemanja Matic was despatched off for a second yellow card.
Christian Kabasele virtually discovered the equaliser in injury-time however his header was pushed broad by De Gea.
Reacting to his goalkeeper’s wonderful save, Mourinho mentioned: ‘That’s the reason why he’s the most effective.
‘That’s the reason he’s Manchester United’s goalkeeper and when you’re goalkeeper of an enormous crew, even should you don’t contact the ball for the entire recreation you must be decisive.’
On his crew’s general show at Watford, Mourinho added: ‘Essential. With this win we maintain the identical factors as Spurs and Arsenal.
‘We have now that distance of 4 and 6 factors to the opposite high groups, if we don’t win this match clearly that distance goes a bit extra.
‘They’re a great crew, they know tips on how to create issues to the highest groups. And I instructed the gamers at half-time that it could possibly be a match to win 4 or 5 nil, or to be in actual bother.
‘Within the second half we decreased our depth, then the objective occurred, then the sport is open.
‘I believe this final Romelu Lukaku sort out as a right-back reveals all the things. I believe he’s the picture of the crew, a crew that performed very properly in lengthy durations within the first half.
‘However we had the expertise additionally right here final season the place they don’t hand over and when the sport is open they imagine.’