Now with just four races to go, winning the championship seems like an impossible task for German Vettel, despite recently having the best car in the field.
Doornbos, a former Red Bull driver, said Vettel’s failed move on Max Verstappen was just the latest example of a critical error in 2018.
“Why did he have to be so eager?” the Dutchman told Ziggo Sport.
“It’s incomprehensible, when so much is at stake for him and his team, to put himself in an impossible position next to Max.”
Doornbos has joined those who think the pressure got to Vettel and Ferrari.
“It went away so quickly,” he said. “After 10 races he was 8 points ahead of Hamilton and 7 races later he’s 67 points behind and it’s over.”
Doornbos thinks the fact that Ferrari has decided to oust Vettel’s teammate and friend Kimi Raikkonen is a sign that the Maranello team “no longer always listens to Seb”.
“Vettel must be challenged and Kimi does not,” he said. “So they’re putting a young dog (Charles Leclerc) next to him and let’s see what happens. It’s time for a fresh wind.
“The mental war has clearly been won by Lewis Hamilton and Mercedes,” he added. “In bad times there is often a hint of panic in Ferrari.”