Manchester United captain Harry Maguire admitted he was confused about the referee giving Fred a yellow card for a headbutt in the first half.

Fred appeared to headbutt Leandro Paredes of Paris Saint-Germain during United's 3-1 defeat at home in the Champions League.

He only got a yellow after the referee went to see the incident on a TV screen.

Fred eventually got a second yellow and went off in the 70th minute as United collapsed in the game.

"It's strange how he gave a yellow card [in the first half]. It's either a red card or nothing," Maguire told BT Sport post-game.

"It's not a yellow card [in the second half]. He wins the ball. I was two yards away, the linesman was five yards [away].

"Every time you go to the floor, especially in Europe, you get a booking."