The 24-year-old Frenchman, who arrived in north London in 2019, struggled for form in his opening season in the Premier League.
But since the summer he has become an integral part of Mourinho’s side, catching the eye with his ability to keep hold of the ball and slalom his way through the middle of the pitch.
And while his improvement has been stark over the past nine months, Mourinho believes Ndombele still has a lot more to offer.
“Tanguy, I have to be honest, Tanguy is the kind of guy who you always expect more than what he gives you, because he is so talented that you always expect more,” the Tottenham boss told Canal+.
“More because the talent is amazing. You know I think by the talent point of view, by the creation in midfield, by the vision, he is second to nobody at this moment in European football.
“But the feeling is always that he has something more to give. He never reaches the limits of the effort, the sacrifice, even the ambition.
“So he is the guy that I love him as a player but frustrates me a little bit because I think he can be much better, much better than what he is.
“When I see for example France and Tanguy was not playing, I don’t blame Didier [Deschamps]. I blame Tanguy, because he’s better than the other guys.
“He should show that every day in training and in every match.”
Ndombele has played 39 times for Spurs so far this season, scoring six goals.
Tottenham missed the chance to move into the top four over the weekend as they were held to a 2-2 draw by Newcastle at St James’ Park.
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