Everton boss Marco Silva accused referee Jonathan Moss of making life "easier" for Manchester United in Sunday's Premier League match at Old Trafford.
The home side claimed a 2-1 win to move above Everton into eighth on the table, courtesy of goals from Paul Pogba and Anthony Martial.
Pogba's opener came after his penalty had been saved by Jordan Pickford, following Moss' decision to penalise Idrissa Gueye for a trip on Martial even though he made slight contact with the ball.
Martial struck a superb second and United missed a number of other opportunities before Gylfi Sigurdsson's spot-kick made the final 13 minutes less comfortable for Jose Mourinho's side.
Silva felt United's penalty was an unfair decision and claimed it cost his side a share of the spoils as his side then had to chase the game.
"It was a tough match, but we came here to win. It is the only way we work. When the game is balanced in the first 20-35 minutes, the penalty starts to put them ahead in the match and more comfortable," he told Sky Sports .
"That moment, it was no penalty. It was difficult for us. That moment makes it easy for our opponents. You are more exposed then because you have to take more risks. They scored a fantastic goal, but we had a good chance to score at 2-1.
"Our one was a clear penalty, not like the first one. The referee is there in that moment and it looks like my player touched the ball. I don't think it is a tough decision. I don't want to talk about it more because I respect the referee.
"One thing is clear is that without that moment, it would have been more tough for them. When you play against Manchester United and in their stadium, they create chances. The referee made things easier for them, but we have to shoot better in some situations."
Silva was harsher in his criticism to BBC Sport , accusing Martial of simulation in his attempt to win the penalty.
"It was not a penalty, [it is] clear the player dived, it leaves a bad sensation," he said. "I told the players at half-time it was not a fair result."