Spurs secured the 19-year-old from Bayern Munich on deadline day, with Postecoglou’s long conversation playing a key role in convincing Tel to join.
Per football.london, despite reports of a veto clause, Spurs are confident Tel will become a permanent signing if they trigger the £45.8 million option.
"He'll be a Tottenham player, mate. He'll be a Tottenham player. I think he'll show everyone he's going to be a Tottenham player in the next six months. I didn't bring him here for six months," he said to reporters.
"It was sort of an exchange - conversation, messages - that lasted a couple of hours and I felt that if I kept him on the phone long enough, I would wear him down. He was falling asleep by the end," he joked. "I got a sense pretty early on that there was a connection there and he was hearing what he wanted to hear. It is a big decision. He is a 19-year-old man at a fantastic football club.
"They would have been quite happy to keep him there I am sure, but he also knew he needed to play. But not just play, play where he is going to develop. I think it is a credit to him that rather than just jump at what came at him, he was very thorough in the way he made his decision."