Abdoulaye Faye believes West Ham are underperforming at Upton Park because the players are being affected by tension in the crowd.
The Hammers missed the chance to take over from Southampton at the top of the Championship after being held to a 1-1 home draw by Watford on Wednesday night.
Manager Sam Allardyce was left unimpressed by his side as they were forced to rely on a late equaliser from substitute Ricardo Vaz Te to rescue a point against the Hornets, who had taken the lead through Sean Murray.
Faye feels that as the race for promotion to the Premier League heats up the East London club need to present a united front on the field and in the stands.
Faye told the Evening Standard: "We are nervous now every time we play at home but that doesn't happen away when we are more confident.
"Everybody should help the team. After two minutes against Watford the stadium was quiet and then, when a player loses the ball, you hear the shouts. That is no good for the team.
"We have got to be stronger mentally when we play at home. At the moment we don't relax but we have to beat Doncaster at home on Saturday. This is a big game for us.
"We have to overcome this mental barrier now because this is an important time and we must win every game. Every player here understands that expectations are high and the fans believe we should win every game."