Sebastian Vettel will keep fighting for the Formula 1 world championship while he still has a chance, according to current champion Nico Rosberg and former Williams reserve and wife of Mercedes motorsport boss Toto, Susie Wolff.

The German dropped 59 points behind Lewis Hamilton after a stretch of two retirements in three races and the third interrupted by engine issues forcing him to start at the back of the grid. 

With just four races left, it means, in theory, a fourth world title can belong to the Briton as soon as the United States Grand Prix next weekend, but Rosberg expects one last stand from Vettel and his team. 

"Ferrari always comes back strong," the 32-year-old said. "[But] it's so difficult for Sebastian now, Lewis has such momentum, everything is going in his direction.

"Sebastian needs a miracle to come back but he's a fighter and he won't give up. It will remain interesting so let's see how far he can take it."

Last weekend, while beginning in a temporary role as a pundit for Sky Sports in the UK, Nico was asked to evaluate his fellow countryman's season, despite its recent slump.

“I think he has done a very good season and has come pretty close to maximising everything that he could,” he commented.

The former Mercedes driver would also offer his views on the respective strengths and weaknesses of the four-time world champion.

“I would say his strengths are race speed and consistency in general. He is always there, always there on Sunday and doesn’t have the big downs," he claimed. "He can be just too hot-headed and too self-confident which in the long run is a strength of his but in some moments it can be a weakness because it boils over."

Talking to Sky Sports Italy, Susie Wolff would echo many of Rosberg's thoughts on the championship and look ahead to the remaining four races.

"When you consider how far away Ferrari was last year, it's been a great turnaround," she said. "In my view, Vettel was just unlucky, Ferrari has a very fast car and I can imagine the title race remaining open until the end.

"It's going to be very interesting because a couple of the circuits [coming up] are not Mercedes circuits or will suit the Ferrari more," the former DTM racer and now advocate for women in motorsport added.

"It's not like last year where it's quite clear what is going to happen so I think we'll see a huge fight."