Daryl Janmaat has apologised after seeing red in the 2-0 defeat at Swansea City.
The Newcastle United full back was shown his second yelow card in the minutes leading up to half-time at the Liberty Stadium after pulling back Swans winger Jefferson Montero.
Earlier in the half he had been booked for a foul on the same player, with Montero getting the better of Janmaat all half.
It left Newcastle, who were already trailing to a Bafe Gomis goal, down to 10 men.
Janmaat said: “I’m very disappointed.
“It was stupid of me and I have to apologise to my teammates, the supporters and everybody, because trying to win a game with ten men is very difficult.
“The first yellow card was clear. The second one, I lost the ball, he (Montero) ran past me and in a split-second I touched him. I pulled him back and that was stupid.
“With 11 men at Swansea it is already hard but with ten men it makes it almost impossible. We didn’t give up though, and the rest of the team gave it everything, but it was a disappointing game.
“We started poor and they got an easy goal. We then came into the game a little bit our performance was not like last week and we have to improve.
“We will learn from this game - you always can learn from defeats - and hopefully we will go and get a result at Manchester United,” added Janmaat, who was speaking to the club’s website.
He will serve a one match ban and miss the trip to Old Trafford.