Manchester United boss Jose Mourinho admits he warned his players of a Watford fight-back at halftime of their 2-1 win.

Only a fantastic stoppage-time save from David De Gea preserved United's second consecutive away win after first-half goals from Romelu Lukaku and Chris Smalling put them in cruise control.

United were clinging on – just as manager Mourinho warned – and he said: “I am very happy with the points, I am very happy with the spirit. But I also feel a little frustrated because we had everything in the first half.

“We let the game go down in intensity and stopped being aggressive. We gave them a chance to be reborn, score a goal and give us a difficult match.

“I told the players at half-time – sometimes I am sorry we don't have a camera in the dressing room because what I said is exactly what happened – that it could be a match for us to win four or five-nil, or to be in real trouble.

“In the second half we decreased our intensity, and Watford are a good team. They know how to create problems for the top sides."