Mauricio Pochettino has warned new signing Serge Aurier he will not put up with any mischief at Tottenham.
Aurier has joined Spurs for £23million from Paris St Germain and Pochettino is hoping the defender proves a reformed character in north London.
The 24-year-old was banned by his former club for directing homophobic language at his then-manager Laurent Blanc and was then convicted of assaulting a police officer outside a nightclub in Paris.
Pochettino places a strong emphasis on discipline at Tottenham and insists he will come down hard on Aurier if he steps out of line.
"I said to him, 'I will kill you', I (would) head-butt him," Pochettino said.
"I think it was good, we had a long chat. He knows very well how we are, what we expect from him and for us it's so important, not only him, every player, how they behave here in the squad.
"We need to keep the dynamic we have created. I trust him, I am confident that he can succeed here and help the team to achieve the things we want.
"When you know and you meet some people, always you start to assess him from the day that you meet them and for me we start from (here) because I don't know him before. For him I think it's a new chapter in his life."
Another player prone to controversy is Dele Alli, who is waiting to hear if he will face disciplinary action from FIFA for sticking his middle finger up during England's win over Slovakia on Monday.
Alli said after the match it had been directed humorously at Kyle Walker, not referee Clement Turpin, while Walker later continued the joke by posting a well-known video of 'Mr Bean' repeatedly making the gesture from his car.
"Look at Mr Bean, no? All the people laugh about that and Dele was joking with Kyle Walker too. Come on. We need to censor Mr Bean," Pochettino said.
"I respect every single opinion but from my point of view, there is nothing wrong from Dele. He is improving a lot. I am so happy with him. His behaviour is improving a lot."
After signing Aurier on transfer deadline day, Tottenham also brought Fernando Llorente in from Swansea and Pochettino believes the 32-year-old will bring a winning mentality to his young squad.
Llorente has won the World Cup and European Championship with Spain, as well as the Europa League at Sevilla and three Serie A titles with Juventus.
"First of all he's a great professional. He's a world champion - he won the World Cup with Spain - and that is the mentality that can translate to us with the experience of winning big things," Pochettino said.
"It's not easy to have the facility to sign players like Llorente. It was an amazing chance for us and I think it's fantastic he decided to sign for us."
Pochettino will have been relieved to keep his own key players this summer but Toby Alderweireld's future remains uncertain.
Alderweireld's contract expires in 2019 and this week his advisor told Spurs either to improve the Belgian's terms or allow him to leave. Pochettino, however, is not worried.
"Toby was talking with me in my office this morning," the Argentinian said. "He's so happy, he wants to make it clear he is fully committed with the club."