F1 sporting boss Ross Brawn thinks Sebastian Vettel has driven his own 2018 championship campaign "off the track".
The Ferrari driver is being roundly criticised for the kind of mistakes he has made at recent races, despite often having the fastest car in the field.
It means Lewis Hamilton only has to finish seventh once either in Mexico, Brazil or Abu Dhabi to be champion, even if Vettel wins all three of those final races of 2018.
Vettel's latest mistakes were in Austin, where he suffered a grid penalty for a red flag infraction, and then collided with Daniel Ricciardo in the race.
"I don't want to attack Vettel, but these mistakes do not seem to be a coincidence," Brawn, the sporting boss for F1 owner Liberty Media, is quoted by Auto Bild.
"They seem to be more of an indication that Vettel is currently a bit off track. It's a shame because Ferrari was able to give him a really competitive car right from the start of the season," he added.
However, Brawn - who was technical boss at Ferrari during the ultra-successful Michael Schumacher era - also thinks the Maranello team has a bigger role to play.
"Ferrari should focus on finding a way to fully exploit Sebastian's talent," he said.
"You do not become a four time world champion for no reason, and Sebastian certainly has not forgotten how to win."
Former F1 driver Mark Webber agrees.
"In an incredibly long campaign like this championship is, driver management is absolutely crucial," said the former Red Bull driver. "Ferrari needs a Toto or a Christian running the show."
