The striker, who made just 11 top-flight starts under Harry Redknapp last season, has started all six Premier League games under AVB this term and netted four goals.
Defoe, who has also regained his position in the England team, looks certain to keep his place when Spurs entertain Aston Villa tomorrow.
He said: "These days I know I'm not going to come off after 60 minutes.
"My form this season has been the result of the manager playing me for the whole game.
"It means I can relax, make sure my movement is good and not panic that I am going to be substituted. I think it is just a case of the manager getting minutes under my belt.
"When you play games, you get fitter and sharper."