Dr Helmut Marko has hit out at F1 legend Sir Jackie Stewart for comments made about Sebastian Vettel.
Stewart suggested that Vettel's title loss this year, as a result of driver errors, indicates the Ferrari driver is past his prime.
"Vettel's mistakes were not about mental weakness," Marko, the Red Bull driver manager who discovered the German, told Auto Bild.
"It was bad lack. In all of those duels, the other driver could easily have been the one who spun.
"To claim that he is past his zenith at the age of 30 is just nonsense," Marko said.
"A four time world champion doesn't forget how to drive. Seb will come back for sure.
"It's like Max Verstappen, who was criticised early this season and came back stronger than ever," he added.