Matthew Upson is expecting the whole team to show their resolve in the weeks ahead - starting with Sunday's FA Cup visit of Nottingham Forest.
The skipper said the squad had spoken about how they can put things right in the wake of Wednesday night's bitter blow of being eliminated from the Carling Cup semi-finals at Birmingham City. The Hammers had taken a 3-1 lead in the tie, only to lose 4-3 on aggregate after extra time.
"It's very difficult," he said. "We discussed a lot of things in terms of the momentum of the game, retaining possession better and taking the sting out of the game. You know that teams like Birmingham, if they have got to score two goals, are going to throw everything at you.
"Trying to the pick the bones out of that afterwards was a painful experience, really. We're certainly disappointed. It's a big low point, but we've got to move forwards.
"We're really disappointed to have got into the position where we were and not made it through to Wembley."
Upson admitted the team needed to focus for the whole 90 minutes, having let winning positions slip out of their hands on several occasions.
"I wouldn't say it's a confidence issue," he said. "It's just our mentality in the second half of late. We played very well in the first half and we've regularly looked in control of the games after 45 minutes this season.
"I think we've shown we're capable of playing good football and grabbing hold of the game and actually looking like we can win them."