West Ham boss David Moyes says they must handle the quick turnaround at Brentford this Sunday.
West Ham face the Bees after Thursday's draw with Europa League opponents Lyon.
"Thursday-Sunday has always proven to be difficult for all clubs in the Europa League," said Moyes.
"I think the quick turnaround makes it difficult but I have to give great praise for how the players have coped with it.
"From our point of view, we were able to cope earlier on because we split the team quite often in the early rounds.
"Everyone stood up for us and got us results. That helped us in the early months of the season.
"Now we're in the knockout rounds, you're having to play all your main players to get results and that's where it takes its toll. But we're still in there fighting and enjoying it.
"We want to stay in Europe and to be there we have to perform well in the Premier League."
The Scot also said: "Brentford have been a good side.
"They were a good side last year, they've come up and have a good first year consolidating in the Premier League.
"They look as if they'll be safe as a Premier League club and you have to say they've done a good job.
"They've got a good model, they've decided the one way they wanted to go and have worked on it for a few years.
"They had a great result at Chelsea last week, but all we can do is concentrate on ourselves."
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