"This has to go down as the blackest day of the season. They were better than us and deserved to win, no question," McCarthy said after the 2-1 defeat at Griffin Park.
"After we equalised we didn't expert to lose, especially conceding goals like that. I haven't got a problem with Brentford or the referee. The only problem I have is with my players.
"I thought DJ Campbell was brilliant throughout. He had two good chances, but I am 47 now and if I was playing he wouldn't have got those chances."