Three-time World Champion Sir Jackie Stewart feels Sebastian Vettel can't be considered a Formula One great just yet as much of his success is owed to Adrian Newey.
Vettel is favourite to win this year's Drivers' Championship after overturning a 39-point deficit in the standings with three consecutive race victories. He now leads Fernando Alonso by six points with only 100 points still to play for this season.
Should he win the title, then Vettel will join an illustrious group of three-time winners yet Stewart believes he still has some way to go before he can be called a great.
"If you've got a superior car, it's relatively easy to win the Championship," he told BBC Sport.
"To really show you're one of the greatest, you have to deliver when you haven't got the best machinery."
He added: "I have the highest respect for Sebastian, but he could not have achieved what he has without the [Red Bull design chief] Adrian Newey factor."
After a slow start to the 2012 season, Red Bull have hit their straps during the latter stages of the season with Vettel and team-mate Mark Webber claiming a 1-2 finish in Korea.
"I'm a big Sebastian Vettel fan," added Stewart. "He completely dominated the Korean Grand Prix and drove in such a mature fashion for a 25-year-old. It was more than impressive.
"Vettel has established himself as the favourite and Alonso is now on the back foot.
"Led by Adrian Newey, Red Bull have bounced back from a slow start to the season and have now come up with superior equipment."
