Alan Pardew thought Dwight Gayle's sending off just before half-time was key as Crystal Palace lost 3-1 to West Ham after late goals from Manuel Lanzini and Dimitri Payet.
Gayle was sent off by referee Mark Clattenburg after receiving yellow cards for late challenges on Payet and Cheikhou Kouyate, leaving Pardew less than impressed with the decision.
Pardew said: "The first challenge from Dwight was a bad challenge and was a yellow card. The second one, he's missed the ball by about a centimetre. Perhaps he shouldn't make the challenge, he'll have to learn from that. Having said that, I still think the referee is hasty there."
The Palace manager suggested Clattenburg may have been frustrated with Gayle after the striker forced Palace's penalty to be retaken after encroaching.
"Perhaps if [Clattenburg] had taken a couple of seconds after the tackle, he might have given him a final warning. I think the game deserved that, because it was a cracking game," he said.
"It was to and fro. West Ham were opening us up, we were getting at them, it was a shame [the red card] knocked the occasion."
Pardew hailed his side's resilient efforts in the second half, but was left disappointed at going down to two late goals.
"It's tough to take," he added. "It's a perfect ball to the far post, you couldn't have anyone better than Andy Carroll on the far post, they've got two poachers at the end of it.
"I've got nothing but praise for my players. I thought they were terrific. I thought West Ham players were terrific."
Get the best features, fun and footballing frolics straight to your inbox every week.
Thank you for signing up to Four Four Two. You will receive a verification email shortly.
There was a problem. Please refresh the page and try again.