West Ham United manager Sam Allardyce believes his side face the second biggest test of all in the Barclays Premier League on Saturday.
In-form Newcastle United visit the Boleyn Ground having won their last six games and Big Sam says that makes them more dangerous than anyone else in the division, except for leaders Chelsea.
West Ham are looking for a first victory in four games following defeat to Everton last time out, with Allardyce looking to the Magpies' recent run as motivation for his team.
He explained: "Alan Pardew's got six wins on the trot and that's a staggering amount of victories coming from what looked like a low ebb of confidence from his players.
"It shows how quickly it turns one way or another - you can never rest at this level of football. It will hurt you if you get complacent.
"They've done magnificently in terms of results and one of the biggest things he's put right is something we've got to do better at, keeping clean sheets."
The boss expects to have two members of his squad back from injury, although having lost a couple more his options are still stretched.
He continued: "I think we'll have Stewart Downing and Cheik Kouyate back and the fact they're back is very important to us because we've got a suspension to Winston Reid and we may not have Mark Noble back.
"We still have six or seven who might be missing, so it's a big test for the squad against the most in-form team in the Premier League, along with Chelsea.
"We have the second most difficult game to win on Saturday, against Newcastle, and it's a massive game for us to try and win."
Mauro Zarate impressed from the bench at Everton last week and the manager has challenged the Argentine to produce that level on a regular basis.
He added: "Mauro came on last week and showed his ability. All he has to do is that on a consistent basis.
"If he does that he plays more regularly. The rotation of strikers we have at the moment is so good - Cole, Carroll, Valencia, Sakho - it's a wealth of good players.
"When you get the opportunity like he did against Everton, do it again and make it better when you get the next opportunity.
"Then you will be starting the game and not coming on as a sub. There's great, great competition, particularly on the front line."