Jose Mourinho said he "cannot keep giving Tanguy Ndombele opportunities" after hauling the midfielder off at half-time during Tottenham's draw at Burnley.
Spurs' £54m record signing was one of two changes at the interval along with Oliver Skipp as Spurs trailed 1-0, and Mourinho insisted Ndombele's performance was not good enough.
Without mentioning Ndombele directly - although he later namechecked him to the written press - the head coach said his side were markedly better in the second half after his exit and the introduction of Giovani Lo Celso and Lucas Moura, as Dele Alli's equaliser from the penalty spot five minutes into the second period earned a 1-1 draw at Turf Moor.
Mourinho told Sky Sports: "I was expecting players not tired to give more to the team, and I think somebody has to realise that this is the Premier League, and this is a new experience, and the first time he comes to Burnley, and I hope next season he can be fantastic because until now it is not enough.
"The quality of Lucas and Lo Celso made a difference. We had something in the first half we didn't have in the second half, so in the second we improved a lot.
"Skipp is a kid and did a fantastic 120 minutes. I needed to protect (Harry) Winks and we managed to have Skipp fresh for Tuesday. He is a kid in evolution and I never want to criticise him in particular.
"I hope that he (Ndombele) uses every minute on the pitch, and every minute knowing what the Premier League, is to improve. There are many fantastic players that in first seasons in new countries, for different reasons, struggle. There are many examples.
"He's a player with a great talent, and he has to know he has to do much better, and I cannot keep giving him opportunities to play because the team is more important than the players, and they must be on the pitch as a consequence of their work and performance.
"I was not expecting to be losing at half-time, and then bring Lucas and Lo Celso on with 30 or 35 minutes left to try to attack the game, but we conceded the goal and the problem was not the goal, but we did not have midfield players to get the ball and assume the responsibility of building from the back. Many times we had to go long because midfield players were hidden.
"In the second half, the midfield players were showing themselves all the time, and as a defender it's much easier to pass, and build, and connect with the attacking players. The number of yellow cards they got was clear of how dangerous and good we were breaking the lines, and it was a very good second half between two teams in different circumstances.
"The attitude was fantastic, it's very difficult to play here, especially when they are in such a positive moment, and of course I am not happy with the result but I'm happy with many things I saw in my players."
Mourinho had already been questioned about Ndombele's commitment in his pre-match press conference, after a video of the midfielder lethargically tracking Pedro Neto during that defeat by Wolves went viral on social media, and had defended him at the time.
Dawson: Transfer fee behind big expectations
When Ndombele arrived in England in the summer, he became Spurs' most expensive signing in history with a £65m price tag on his head. However, injury and form have seen the ex-Lyon man make only 12 Premier League starts in his debut season to date.
Speaking on Sky Sports after Saturday's game, former Spurs captain Michael Dawson said the size of Ndombele's transfer fee had created a level of expectation the player had yet to meet.
He said: "When you get bought for that kind of money, you come with big expectations. He has to perform, Jose spoke about him a few weeks ago, and he's carrying a big price tag, and he's going to have to do that.
"Get on the ball when he plays, have energy, you have to have it in the Premier League, you can't play at your own pace. You've got to get after it.
"Spurs were under the cosh in the first half, and you have to show a different quality, a determination and aggression, and that's probably what Jose was talking about."
Dyche: Wood gets penalty if he 'rolls around'
Burnley boss Sean Dyche took issue with the decision not to award his side a second-half penalty when Davinson Sanchez clearly appeared to barge Chris Wood in the back moments after Spurs had been awarded a spot-kick of their own, with neither referee Jon Moss nor VAR official Craig Pawson convinced by the incident.
Dyche said: "We've got to be careful where the game's going. I've talked about it all season, people falling all over the place - we saw it with Joe Gomez today. He gets pushed in the back, I guarantee if he flails his arms around and rolls around it's given. He doesn't and I'ts not given, and Bournemouth get a goal from it.
"A similar thing happens with Chris Wood, he's trying to bring the ball down on his chest and turn in the box, bloke comes through the back of him it's a definite penalty not given. If he falls on the floor flailing his hands around or whatever they do, he probably gets it.
"There were some words at half-time from a few of the [Spurs] staff, and I thought the referee changed his performance after that. You hope it doesn't, but second half everything seemed to be given for very little."