Paul Pogba admits he made a "stupid mistake" when he tripped Hector Bellerin to concede a penalty in Manchester United's 1-0 defeat to Arsenal.
The midfielder clipped the Gunners full-back's ankle in the United box, prompting the referee to point to the spot.
Pierre-Emerick Aubameyang converted the spot kick to seal the victory for the away side, consigning the Red Devils to their third Premier League defeat of the season.
Pogba admits his side were not at their best in the clash at Old Trafford and suggested he gave away the penalty because he was "out of breath".
"We know it's a poor performance. Myself, I cannot give a foul away like this," he told BBC Sport .
"I thought I would touch the ball but I didn't. I cost us the goal today with the penalty.
"Like I say, details. We have to do better, the team, myself, it starts with me.
"I felt like I touched him a bit, I knew I was in the box, I shouldn't have given a penalty away like that. Maybe I was a bit out of breath, it made me do this stupid mistake
"I will learn from that, I'm not the best defensively in the box, I can work on that.
"We also need to do more with the ball creating chances. We didn't expect to be man for man, but after this we can adapt, we have to find a solution but we didn't. That's why we weren't dangerous with the ball.
"But like I say, the team performance needs to be a lot better."
United boss Ole Gunnar Solskjaer was disappointed in the France international for making such a mistake.
He told Sky Sports : "He needs to stay on his feet. Paul [Pogba] knows it’s a soft penalty to give away, similar to Nemanja [Matic] who almost got a penalty."
United will look to recover from their latest defeat on Wednesday when they travel to Istanbul to face Basaksehir in the Champions League.
They will then return to Premier League duty with a trip to Goodison Park to face Everton on November 7.