Bissouma struggled to assert himself as a key player in his first campaign with Spurs last season before suffering a serious ankle injury. But he has started the new campaign as an integral member of a midfield three alongside Pape Matar Sarr and James Maddison.
Speaking to talkSPORT on Tuesday, new head coach Postecoglou revealed: “I don’t think I’ve done anything specific with him. I was lucky because he was here the first day I arrived. A lot of the boys had played international football but Biss was here from the first day.
“I kind of grabbed him and, the way he was training at the time — the first three or four sessions we mainly had young guys — I said: ‘You can be a leader in this group.’ I already knew about his ability but the way he was training, I could see he got a lift from that.
“He was late the next morning and again I said to him that to be a leader means being on time, and he’s been good since then.”
Tottenham’s most high-profile recruit this summer was £40million signing Maddison, who joined from relegated Leicester.
“We signed James pretty early on, which was pretty great for me”, Postecoglou said. “There was competition from other clubs for him but the club backed me early on to bring him in.
“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.
“He’s coming here to make an impact, not just for himself individually because I think he’s already done that as an individual. He wants to make an impact for this football club and I think for James Maddison and all the players, we’re just at the beginning.
“Madders and Sonny [Son Heung-min] and [Cristian] Romero, who are the new leaders of this group, are going to play an important role in that. I keep saying it’s their dressing room. It’s got to be driven by them.”