"I'm angry and the players know I'm disappointed," Moyes said.
"In the main we were very good but for a couple of really silly mistakes. We offered a threat, as did they. The performance was good but it's tarnished by a couple of mistakes.
"We gave them a leg-up for 3-1 with the own goal, and we gave them a massive leg-up with 20 minutes to go."
"Their effort was huge. I just feel playing Liverpool on Wednesday night and fatigue played a part in the second half."
Brighton manager Graham Potter: "I'm very proud of the players - proud of their reaction to being down in the game. We had to suffer a bit.
"Mistakes don't just happen on their own. Something has to force them to happen. We pushed and pushed.
"In the second half the game was played in the opposition half and their keeper has made more saves than ours."
On the death of his father on Thursday: "It's been tough. Thankfully I've had a lot of support from the club. My father was proud of me and proud of what I did, so it was my job to do it the best I can."