West Ham manager Slaven Bilic has warned his team Crystal Palace's poor Premier League form in recent months counts for nothing in Saturday's meeting at Upton Park.
Palace last won a league encounter on December 19, when they beat Stoke City 2-1, and have since gone 13 games without victory.
They have progressed to the semi-finals of the FA Cup, though, and Bilic is adamant West Ham - who are one point outside the top four and unbeaten in their last eight games in all competitions - cannot afford to take this weekend's match lightly.
Bilic said: "Palace are the best example of why Premier League managers are wary of good form. This calendar year has been great for Palace in the FA Cup as they are through to the semi-finals, but in the league they haven't won in 13 games.
"Their confidence has gone down and you start to lose matches without knowing the reason why it is happening. Then it continues and you are in trouble.
"They have been unlucky in their last couple of home games, especially against Liverpool. It's still a very dangerous game for us. They have a very solid team, have pace up front, so it will be difficult for us, of course.
"I don't think Palace have to change the way they play, with their counter-attacking, but they just need to start converting their chances."
Bilic will have to make do without the services of James Collins (hamstring) and Sam Byram (muscular) due to injury, but James Tomkins returns after shaking off a calf problem.
Crystal Palace may be short on confidence following their disappointing league form, but recent results at Upton Park should provide reason for optimism.
Palace claimed a 1-0 victory in April 2014 and were 3-1 winners in last season's corresponding fixture.
Alan Pardew's men will be looking to make it three away wins in a row over West Ham, but the Palace manager realises a tough task awaits.
"It's a tough game. We've played well there in the last two years and we'll need to do that again. We've no momentum in the league. We need to get a victory, grind it out and fight for everything," Pardew said.
"West Ham have done well this year. The manager has done a super job.
"Dimitri Payet is a guy who is at the top of his game. Without a doubt - outside of the Leicester boys - Payet is the best outfield player this year."
Palace will be without James McArthur due to an ankle problem, while Connor Wickham is also unlikely to feature because of a thigh injury. Yohan Cabaye, Emmanuel Adebayor and Mile Jedinak are all doubtful due to knocks.
Key Opta facts:
- The last three Premier League meetings between West Ham and Crystal Palace have ended as 3-1 away wins.
- West Ham have conceded the highest proportion of top flight goals in the first half of matches this season (60 per cent).
- Crystal Palace sat fifth in the Premier League at the end of 2015. Since then they have dropped to 16th. They are the only side in the top four tiers yet to win in 2016.
- Since the start of last season, Dimitri Payet has created 221 chances, more than any other player in the top five European leagues in that time.
- Wilfried Zaha has won more fouls than any other player this season (77).