Mauricio Pochettino says Dele Alli must learn that his diving does not do Tottenham Hotspur any good, after the midfielder was booked for diving in Saturday's 4-0 win over Huddersfield Town.
With Spurs leading 3-0, Alli went down in the box under pressure from goalkeeper Jonas Lossl, but the 21-year-old was already falling and was shown a yellow card for his attempt to win a penalty.
The England international has been criticised for diving before - most notably for a successful attempt to get a spot-kick against Swansea as well as in matches against Fiorentina and Manchester United last year.
And his latest attempt has disappointed his manager, who believes he must learn to stay on his feet instead of trying to con the referee.
"I didn’t see it," Pochettino said in his press conference after the win. "But if it was like this then he needs to learn. He must learn.
"This type of action doesn’t help him, doesn’t help the team and doesn’t help football.
"We have been talking in the last few years about fair play, to be honest. I think he is improving a lot and learning but still he must learn."
Alli's booking was a minor note in Spurs' victory. Pochettino's side were 3-0 up within 25 minutes through a Harry Kane double and a Ben Davies goal before Moussa Sissoko's late strike.
Kane is now on 84 Premier League goals - as many as Cristiano Ronaldo scored during his time at Manchester United - and he was given a standing ovation by the whole stadium as he went off in the second-half.
Pochettino was elated to see the home fans applauding the striker after another impressive display.
"Fantastic. I am so proud to be a manager in England," he said. "Today that was fantastic from the Huddersfield fans. To recognise one of the best players in England. His country loves him. That is so important. I enjoyed it a lot.
"The stadium, everything makes us very proud to be here in the Premier League in this country. I am so happy to manage here."