Defoe joined the Black Cats during the January transfer window and he seems to have made a positive initial impression on the rest of the squad already.
The England international has two goals to his name in his first five appearances and Graham believes that he is helping to improve the standards of the rest of the strikers at the Stadium of Light.
“To have someone like that at the football club has given everyone a massive boost," Graham said.
“It’s upped everyone’s game and I think you can see that from the last few weeks. He’s done it all his career.
“He’s keeping everyone on their toes and everyone wants to be playing up front with him. It’s good to have that competition.”
Graham's effusive praise of his new teammate may come as a result of his chances actually being improved by Defoe's arrival.
Poyet has switched to a system that utilises two strikers since Defoe joined and Graham's career at the Stadium of Light has been saved because of it.
The 29-year-old appeared miles away from the first-team at the start of the campaign, but he started against Swansea City this weekend and now will be looking to hold down that place.
Doing so could be difficult - with Connor Wickham edging closer to fitness - but Graham certainly seems to be confident at the moment and he will be hoping that he can start getting on the scoresheet alongside Defoe in the coming weeks.