Swansea City midfielder Jonathan de Guzman admits Manchester United's fans helped them to their shock FA Cup win on Sunday.
De Guzman says the home support "turned their backs" on United's players.
"You could tell their fans weren't pleased when they played the ball backwards and we used that to our advantage," said the 26-year-old.
"You could feel [edginess in the stadium]. The fans wanted to win.
"They are at home. Their crowd is an extra man. But if they are turning their backs or things are not going well and the team is not playing the way they should, as an opposition player you have to use that.
"You could hear the fans booing at the end of the game and when they played the ball backwards we knew that as well."
