Gerhard Berger is not so sure that Lewis Hamilton is the best F1 driver of all time.

This year, Lewis Hamilton looks certain to win a sixth drivers' world championship. Only Michael Schumacher - with seven titles - was more successful.

"He is a great driver," F1 legend Berger told Abendzeitung. "But the best of all time?

"Of course, statistically, he has the opportunity to overtake Michael Schumacher. He's doing a great job. But this question all the time of who is the best ever? It's so hard to compare."

As Hamilton thrives, some are saying that quadruple world champion Sebastian Vettel's best days are now behind him.

"I still trust Sebastian a lot," Berger insisted.

"He's a clever guy, even if it's a bit difficult for him at the moment. There have been a few mistakes, not only by him but also by his team. Then he also had bad luck.

"But one must not dismiss Sebastian. Not for nothing did he become world champion four times," he added.

Berger, who now runs the German touring car series DTM, is also not surprised about Mercedes' ongoing success, even following the death of Niki Lauda.

"Toto Wolff learned a lot from Niki, so it's not surprising," Berger said.

"The team is very well positioned. They make very few mistakes."