Former AlphaTauri team principal Franz Tost believes a prime Sebastian Vettel could win more races than Max Verstappen if he battled him in equal machinery.
During his time at the helm of Red Bull's sister team, he developed the careers of several drivers including Vettel, Verstappen, Daniel Ricciardo and Carlos Sainz.
Vettel claimed AlphaTauri's, then known as Toro Rosso, first victory in the sport at the 2008 Italian Grand Prix, before going on to win four world championship titles with Red Bull.
Verstappen, on the other hand, has recently overtaken Vettel on the all-time list of race winners at the age of just 26, but has one fewer world title to his name.
"Vettel and Max - because of their dedication to the sport and their speed," Tost said.
"They know how to win races and they also bring all the factors with them, what you need to win races.
"This is, first of all, the talent. You must be highly skilled for driving such a car. Second, the passion. Both of them are very passionate.
"Look at Max, he is driving this e-car series and all this kind of stuff. Isn't this fantastic? A three-time Formula 1 world champion and at home he is racing against others on the computer.
"Then they are disciplined. They know exactly when and what they have to do.
"The discipline is a very, very important factor, and then to study the rivals, to find out where are the deficiencies and to work on this to beat them.
"These are the factors both of these drivers have, 100 per cent."
Asked who would win the qualifying head-to-head between the pair, Tost replied: "Verstappen."
However, when quizzed on which driver would win more grands prix, he said: "Could be Sebastian."