Jose Mourinho said “individuals felt the pressure” in Sunday’s 3-1 defeat and singled out Luke Shaw’s mistake in Watford’s second goal.
Shaw’s error was highlighted by Mourinho, who was unhappy with the England international’s positioning for Camilo Zuniga’s strike, with the Portuguese admitting it is up to him to drill his approach into his squad.
“Their second goal is a mistake that goes against our plan and our training, because our intention was for their wing-backs to be pressed and not let them progress,” he said.
“(Nordin) Amrabat receives the ball and our left-back (Shaw) is 25 metres from him instead of five. Even at 25 you have to jump and go and press but no, we wait.
“This is a tactical but also a mental attitude. It’s something that doesn’t become perfect in a couple of weeks. So we have to improve, no doubt, individually and collectively. And that’s my job.”
Asked if United’s drop in form was worrying, Mourinho added: “My feeling is that it is not because we started the season very well with (winning) the Community Shield and three victories in a row in the Premier League.
“(That is) the best start that a new manager has had at Manchester United I think. But was I thinking that my team was ready, perfect, unbeatable? Not at all.
“I was completely aware that we were not perfect, with lots of players who are not end products and can make their own mistakes…I feel that some individuals probably feel the pressure and responsibility too much.”