Sam Allardyce has told his players that the match against West Bromwich Albion on Saturday is "becoming a must-win".
The Hammers lost 3-1 to Arsenal on Boxing Day to fall to 19th in the Premier League.
They have now picked up just four points from their last six matches and have won only one of their last 11.
Speaking after the defeat to the Gunners, Allardyce said that his players have to step up against West Brom and cut out their silly mistakes.
"West Brom is becoming a must-win, so we have to go all out without being over anxious or over adventurous," he told The Mirror.
"We can't start leaving backdoors open and start conceding too many goals, we're going to have to score far more goals than we concede to win a game of football.
"Our big games are the West Broms and Fulhams in the next two games. It is about performing like that against those clubs, which give you a better chance to win the game."
West Ham's last win was a 3-0 home success against Fulham at the end of November.
