Verstappen clinched his third consecutive title in the Qatar GP sprint race on Saturday to secure a crown that has looked to be his since the early phase of the campaign.
But while the RB19 car has been the class of the field, Horner feels that it has been made to look even better by a trait that Verstappen has of needing to show just how good he is.
Rather than ever taking things easy and going into cruise and collect mode, he says Verstappen’s mentality is that he must win by the biggest margin he can.
“He doesn't leave anything on the table,” said Horner. “He wants it all. And that drives and motivates the team internally.
“I think he is relentless in his pursuit of performance. He doesn't want to just win: he wants to dominate.
“You see that in any great sportsman. Their pursuit of excellence and pursuit and not just wanting to be first, but certainly dominate, is again a hallmark what makes him such an exceptional talent.”
Horner believes that what Verstappen has shown this year is not just confirmation of the natural talent he has had ever since he arrived in F1, but also an added maturity that has made him a complete article.
“I think generally he always had the speed from the very moment he sat in the car, and I think that he now couples that with experience,” added Horner.
“He arrived in F1 as quite a rough diamond, but now is a very polished diamond. I think that he's maintained all those raw attributes that he had, but now brings experience and couples that with that.”
He added: “Some of the races he's driven this year have been so great that it's exceeded all our expectations.
“I think Max as a driver has just continued to evolve, he's continued to grow and the level that he's now operating, and the way he's able to read races, the way he is able to manage tyres, the mental strength that he has in the high-pressure moments is absolutely outstanding.”
Verstappen himself believes that taking on board a lot of life lessons over the past few years has helped lift his own potential in the car.
“I keep trying to improve,” he said. “And of course, I don't necessarily think I have become a faster driver, but you have a lot more experience in the car. You grow as a driver, you grow also, I think, as a person in life.
“I think all these kinds of things, when I compare to my first season in Formula 1, they help you a lot in terms of just dealing with every kind of pressure situation throughout the weekend; everything that might be thrown at you and in difficult conditions, for example.
“In the end it's all about trying to deliver every single weekend, which I think is very hard in Formula 1.”
