Dempsey is beginning to establish himself in the first team after moving across London from Fulham at the end of August.
He said: "It was a big boost for us to have Adebayor coming back to fitness against Villa.
"You could see his quality when he came on. There is more competition for spots now and that will push everyone's game up to another level.
"Adebayor has confidence and you can tell he enjoys the game. He is someone who is very talented on the ball and he is also an unselfish player.
"If he can give someone a goalscoring opportunity, he will always play him in.
"He does a good job keeping possession and he always works really hard for the team.
"It's great to have a player of his quality and it is fun for the rest of the team to play with someone like that."