Bruno Fernandes called on his Manchester United teammates to thank the away fans after defeat at Newcastle United.
Second half goals from Joe Willock and Callum Wilson condemned United to their latest disappointment in the Premier League.
Lisandro Martinez was seen punching the bench upon his substitution, while Diogo Dalot and Antony were seen in an angry row at the final whistle.
Antony had also been taken off near the end.
Fernandes also demanded teammates who were trudging towards the players' race to stop and acknowledge the away support.