Spurs were sent crashing out of the FA Cup at the hands of Championship side Leeds last weekend, before being held to a 1-1 draw by Norwich in the Premier League on Wednesday.
Andre Villas-Boas' side will get another opportunity to put things right against West Brom on Sunday, with it possible that they could close to within a point of third-placed Chelsea.
Dembele hopes they will return to winning ways at The Hawthorns, with it important to start building momentum again.
He said: "We've been disappointing this week.
"The good thing is we now have a lot of games to put things right and I think we have the confidence to win at West Brom.
"We find it more difficult against smaller teams.
"West Brom are not that far away from us, so we know what we have to do."