The Belgium international was unable to help Tottenham avoid a 3-0 loss to struggling West Ham United at White Hart Lane on Sunday.
André Villas-Boas’ remained stationary in sixth place following the shock London derby defeat, falling further behind the top-flight’s early pace-setters Arsenal and Liverpool.
And Dembélé warned Spurs that they can ill-afford to drop points against teams which the north London side should be beating.
“If we want to be there with the top four, we need to win these games,” Dembele said.
“You see the top teams, if they want to be champions, they have to win these smaller games and you can see it’s the difference with the guys who become champions, they win these
“It’s easier to play against the top teams for the motivation but if we want to be a top team, we need to be concentrated for these kind of games,” the Belgian said.
“It’s a mental thing. We have to talk with the team and we need to concentrate each other. It’s normal.
“We have a lot of players and you can change very quickly the team, so everyone needs to know it’s a difficult season.”
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