West Ham boss David Moyes said his side were made to pay for their mistakes in a 3-1 defeat at Brighton this afternoon.
Glenn Murray gave Albion an early lead but Javier Hernandez drew the Hammers level on the half-hour mark.
Jose Izquierdo's stunning strike put Brighton back ahead on 59 minutes, before Pascal Gross drove home the third on 75 minutes.
Moyes said: "I was totally frustrated by the goals we conceded.
"When I first came in, I thought we gave away too many individual error goals and today we gave the ball away (too much).
"That allowed their first goal after we gave away a pass.
"The second one we gave away with a pass, so a lot of it was our own downfall.
"That's not to say we played well enough with it anyway, so they were the disappointing things.
"I think we could have dealt with the ball before the corner (for the second goal), I don't know if Adrian could have come and taken it. From the corner, we clear it and to be fair the boy scores a worldie.
"That made it an uphill battle after that."
Moyes added he felt West Ham grew into the game after Albion's early opener and said: "I didn't think we started very well but we grew into it.
"They had bits of control and we had bits of control. I thought in the second half, 'let's make sure we stay in the game and don't be stupid with anything we do' but we made mistakes and that cost us."
Keep up with all the top football news and transfer gossip from England, Scotland and beyond with footballwire.co.uk