Harry Maguire is confident Manchester United will recover from their nightmare Champions League start but knows they have to cut out the ill-discipline and errors that cost them in the defeat to Young Boys.
A kind-looking group started with the Red Devils' easiest away match, yet Ole Gunnar Solskjaer's stuttering side came a cropper in Switzerland on Tuesday evening.
Cristiano Ronaldo opened the scoring at the rocking Stadion Wankdorf, but Aaron Wan-Bissaka's red card in the 35th minute put United on the back foot.
Nicolas Moumi Ngamaleu deservedly drew Young Boys level in the second half before a careless Jesse Lingard backpass allowed substitute Jordan Siebatcheu to seal a stunning 2-1 stoppage-time win.
"Of course discipline is a huge part of tournament football," United captain Maguire said.
"For example, if this was a knockout game and we go out of the competition because we go down to 10 men, I am sure everyone will be kicking themselves.
"It's fortunate that it is the first game of the group and we have loads of time to bounce back from it.
"In terms of Jesse, obviously no footballer likes making mistakes but it's part and parcel of the game.
"And then we've come out in the second half and I felt we looked controlled without the ball, without being a huge threat on the counter-attack.
"Obviously we could have done more on the ball but without the ball I felt they didn't really create big opportunities.
"The first goal is unfortunate, the deflections and ricochets. I don't know who it ends up going in off.
"The last goal is a mistake, which obviously happens in football, but it's unfortunate again.
"In terms of the shape without the ball, I felt it was a lot better when we went to a back three slash back five. Obviously with the counter-attacks, we maybe could have done a little bit more."
