Andre Villas-Boas' wait for his first win in charge was prolonged last weekend when his team conceded yet another late goal to draw 1-1 at home against Norwich.
Boos greeted the Spurs team as they left the pitch - both at half-time and full-time, and critics within the game - including former England striker Alan Shearer - have cast doubt on whether Villas-Boas is the right man to lead the London club forward.
Dembele thinks Dempsey, a £6million deadline day signing, can provide the cutting edge that Tottenham currently lack, however.
Dembele, who like Dempsey swapped Fulham for Tottenham last week, watched the American rack up 23 goals last season and is sure that the 29-year-old can go on a similar run at his new club.
"Clint always is so dangerous," Dembele said.
"I sent him a message saying I was very happy because he is a fantastic player. He is a good boy so I am very happy that he is here.
"He is so hungry to score goals. He fights a lot and it is fantastic to have him in the team.
"He works as hard as two men so I'd prefer to have him in my team rather than play against him."
Dembele, who also starred at Craven Cottage last term, made the perfect start to his Tottenham career by coming off the bench to put the home side ahead on Saturday after a drab first-half performance from Villas-Boas' team.
Robert Snodgrass' late equaliser meant the Belgian had to settle for a draw on his debut, which disappointed him given that he helped Fulham hammer the Canaries 5-0 on the opening day of the season.
"I scored a goal but I would be happier if we got three points," Dembele said.
"It's difficult to tell what the difference was (between the two games).
"Norwich played different today [Saturday] (to the Fulham game), but we have a fantastic team here. This is a very big club. The stadium is nice and all the boys were fantastic with me when I came in. "It's a very warm club. That's why I chose Tottenham."
Some of Norwich's players expressed their shock that Dembele did not start at the weekend given that he was the architect of their thrashing on the opening day of the season, but the 25-year-old was content with his role as a substitute.
"For me it wasn't bad because I could see how the team plays," Dembele said.
"I could keep an eye on how the team plays and see what I would have to do so when I came on it was OK."
Dembele also had nothing but praise for the management style of Villas-Boas.
He said: "It was very clear what the manager wanted me to do. He said to me: `Play your game like you always play' and he tried to give me the confidence. That's the only thing a player needs."