The pressure is on Spurs to re-establish their four-point lead over Arsenal ahead of next Sunday's north London derby at White Hart Lane.
"We don't have to fear any team," said Dembele, who secured a 3-2 aggregate Europa League win over Lyon in midweek with a 90th-minute equaliser in the Stade de Gerland. "People have respect for us. If you're in a winning mood it's important in the league."
He added: "We have two more very important games coming up in the league so the confidence will stay high and that's good for us."
Given the gulf in ability between the two sides, West Ham are expected to approach the derby cautiously.
Tottenham have struggled at times to break down teams who shut up shop. They have often had to rely on the brilliance of Gareth Bale to find come away with three points, but Dembele is confident Spurs will be able to overcome their rivals on Monday regardless of the tactics they employ.
"It will be a different game to the Lyon one of course," Dembele said. "Teams always have a lot of respect for us and they drop back so it's always difficult, but I think we need to do the difference, we have to fight for each other as well. It will be a physical game, for sure, but we are used to it and this is a special match for us and the supporters too because it is a derby."
Manager Andre Villas-Boas now hopes the result in Lyon, which set up a last-16 tie against Inter Milan, will inspire his team to victory at Upton Park.
"We've been having some great, great results," the 35-year-old said. "After Europa League games we've always been good in the Premier League. I think it puts us in a good position to face West Ham.
"I don't think it's a distraction, I think it's an inspiration and I hope it can be exactly that against West Ham."
Source: PA
Source: PA