Maddison joined the north London outfit on a £40m deal from Leicester City after the Foxes suffered relegation from the top flight last term.
The England international has made an instant impact in Postecoglou’s team as he has already made four-goal contributions in four league matches.
The Australian stressed that Maddison is a player of outstanding quality and he is very driven to bring success to his new club.
Postecoglou also revealed that Spurs’ management backed him to sign Maddison early in the transfer window, despite competition from other clubs.
“Oh absolutely”, Postecoglou told talkSPORT when he was asked if there is more to come Maddison.
“When you talk about the support I’ve had since I came into the role, we signed James pretty early on which was pretty great for me.
“There was competition from other clubs for him but the club backed me early on to bring him in.
“I think what you’ve seen so far is that we’ve gained a player with outstanding ability but also somebody who is very, very driven to bring success to this football club.
“I think when you get both, sometimes you get players at different stages of their careers, but for James and the club it’s the perfect time.”
Maddison will be looking to continue his good early season form when league matches resume following the international break.