"We had three or four very clear chances and their goalkeeper made some very good saves," he told Sky Sports 1.
"It is very hard to take because we had the feeling that we did everything to win that game.
"West Ham had one or two chances but other than that, they didn't create anything else so we felt like we should have won the game."
"It's disappointing because in our two home games so far we've done everything to try and win the game," he added.
"We had a good first result at West Brom but haven't really built on that. Now it is up to us. Next week we have a very hard game at Anfield so hopefully we can improve this week and score some goals."