Manchester United manager Ralf Rangnick criticised Bruno Fernandes for his role in Crystal Palace's winner.
Fernandes attempted to play a blind pass from a throw-in but the ball fell to Wilfried Zaha, who bypassed Diogo Dalot and Victor Lindelof to score the only goal of the game.
Fernandes made an identical error in United's 4-1 thrashing at Watford in Ole Gunnar Solskjaer's final game in charge in November which contributed to Scott McTominay giving away a penalty.
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Despite a 12th Premier League defeat of the season, United finished sixth to qualify for the Europa League as West Ham lost 3-1 at Brighton.
"Yes, I think Brighton did us the favour to turn the game around, they were losing 1-0 at half-time and scored three goals in the second-half," Rangnick said. "That was the good thing about this weekend and this fixture.
"We would have loved to take care of it ourselves but the game was indicative of the last couple of weeks, especially when we played away from home. We tried.
"I think we had three good opportunities to score ourselves in the first-half but we didn't and, especially in the first-half, we had too many unforced errors and bad giveaways, that is the way we conceded the goal. In fact, it was our assist, the goalscorer, in the end, was Zaha but the ones who gave the assist were ourselves.
"There was a throw-in - just keep the ball into our own half - and the way we defended that shot was also not the way that you have to defend in this league and that's why we were trailing again 1-0.
"At half-time, we were trying to bring on all the young strikers we had on the bench. We had some opportunities in the second-half but it was not clinical enough and that's why we lost again away from home."
