Valtteri Bottas will come back stronger in 2018 as a result of the lessons he learned during a difficult first season at Mercedes, according to Toto Wolff.

Nico Rosberg’s shock retirement at the end of the 2016 season – having just won the drivers’ championship – left Mercedes looking for a replacement at short notice, with Bottas getting the drive little more than a month before pre-season testing began last year. A strong start featuring pole position in Bahrain and a win in Russia gave way to a difficult season as the Finn’s title challenge faded and Lewis Hamilton secured his fourth world championship.

Wolff says Bottas must fight for the championship when driving for Mercedes and expects to see a stronger performance this coming season.

“That’s what he has to do [challenge for the title],” Wolff told ESPN. “We have seen some highlights in Sochi and in Austria and then after the summer Lewis came back very strong and the step that Lewis made up, Valtteri went backwards.

“He recovered at the end of the season and he is a Finn with a strong never-give-up mentality – Sisu – and I expect him to come back strong with all the learning he has done during the season against the best Formula 1 driver of the current day and age.

“I think he’s the first one who wants to prove it to himself. He knows the deficits he had during the season and he knows where he had advantages.

“Valtteri, I’ve known for ten years and ten years ago a little kid showed up in the winter in my office with a little pullover, no jacket, no father with him, and he has a super-strong will, an iron will and character, and I have no doubt we will see a better Valtteri in 2018.”

Asked if he feels Mercedes has the best driver line-up in Formula 1, Wolff added that it is impossible to tell without all cars being equal.

“Some of my colleagues throw these things out – ‘we have the best driver line-up’ – who knows? I think we have a very strong driver line-up, we won the constructors’ championship and we won the drivers’ championship, and the stopwatch never lies so it looks like we had the best.

“But then of course Daniel [Ricciardo] and Max [Verstappen] are very strong, Kimi [Raikkonen] and Sebastian [Vettel] are very strong. I like [Esteban] Ocon and [Sergio] Perez. Who knows, maybe you put Ocon and Perez in a Mercedes and they would win championships. So the answer is I don’t know.”