“Maybe you don’t want to hear it, but maybe you do know that in professional football you make professional fouls.”

That was the view of Louis van Gaal after Wayne Rooney was shown a straight red by referee Lee Mason for a challenge on Stewart Downing in Manchester United’s 2-1 victory over West Ham.

“I saw that today, five or six times and Wayne has done it also. Professionally as a trainer-coach, I can see that, but I think he did it too unfriendly,” continued the Dutchman.

“That is his biggest mistake. But I also saw professional fouls without a red card or a yellow card, so that is a little strange.”

The United and England captain had opened the scoring for the home side after just five minutes — his 175th league goal of his career — before Robin van Persie doubled his side’s lead on 22 minutes.

With a lack of recognised centre-backs at his disposal, van Gaal gave a debut to 19-year-old academy player Paddy McNair who signed from Ballyclare Colts four years ago.

But following last weekend’s 5-3 humbling at the hands of Leicester City, the Red Devils’ defensive frailties were once again highlighted when Diafra Sakho nodded home his fourth goal in five games.

The home side were forced to play the majority of the second-half with 10 men following the dismissal of Rooney just before the hour mark.

It was the the first time Rooney had been sent off in the Premier League since March 2009. He will now miss the games against former club Everton, West Brom and Chelsea.

The visitors had the chance to take a share of the spoils in the dying moments of the game only for substitute Kevin Nolan to have his effort ruled out for being offside.

After the game Hammers boss Sam Allardyce claimed the assistant referee had “dropped a massive bollock.”

He said: “The superman linesman’s got X-ray vision. Somebody has suggested his (Nolan’s) head was offside. If he can see his head is offside then he’s a superhuman being for me.

“I thought it was onside, I have no doubt in my mind and it would have got us a 2-2. But it’s our own fault today. Assistant referees and referees make mistakes, we have to accept that.”