Leicester City boss Claude Puel says they cannot take lightly struggling West Ham on Friday night.
The Foxes make the trip to the capital for David Moyes' first home game in charge of the Hammers after he was appointed earlier this month.
"West Ham fans want a reaction," Puel said. "We know this team are at home with a new manager and we want to show good qualities.
"When a new manager arrives, it is always positive for the players to show their qualities and to try and win their place.
"It will be a strong game and it is important to keep focus. It's a difficult game for them but also for us.
"We know it will be a difficult game. They have changed their manager like Everton did when we played them.
"It is a new challenge for us because we know the players of West Ham but they have had just one game played under the new manager at Watford."