The goalless draw in the third round of the FA cup has set up a replay at the London Stadium.
"I've seen us do better but we haven't come up against individuals as good as today," he said. "It sounds silly but we've had tougher games and that's why I thought the game was there to be won.
"Wigan, Blackburn - we've got them to come in the next league fixture - and different types of games.
"I don't mean that as being disrespectful to West Ham but I really felt the game was there to be won.
"It's easier said than done, you score every chance when you're on the touchline, but nerves play a part.
"We wanted to make it uncomfortable. The danger is you have all the hype and build-up but then fall flat on your face. That didn't happen."