"It was two errors on our part for their first two goals, at that stage we worked really hard to get 1-0 up and we worked hard throughout the game. But even after playing so well if you gift them two goals it's difficult to get a result," BBC Sport quotes the West Ham manager as saying.
"The second half they scored from a long ball and the defending was pathetic on our account. There's no satisfaction at playing okay as football is about winning and getting results, we didn't do that tonight and all of our hard work was wasted. We knew that Arsenal had a lot of games and a lot of injuries lately and we took the pressure off them.
"It's down to us why we lost the game and why we haven't got anything out of the game tonight."
The result leaves West Ham 11th in the Premier League table, seven points clear of the relegation zone.