Third-placed Spurs have not lifted the league trophy since 1961 but Defoe believes they are well-positioned to pull off a shock this season.
"I'm going to say what the manager says - it's not impossible," he said. "I think when you really believe anything is possible.
"The way we're playing is fantastic. The chances we're creating, the intensity we're playing at, the way we move the ball; it's just been great.
"It's a good time to be at the club, everyone is enjoying it."