Mercedes team boss Toto Wolff says Valtteri Bottas has the ability to fight Lewis Hamilton and Sebastian Vettel for the world championship this season.
"That's what he has to do," Wolff told ESPN in an exclusive interview this week, when asked if Bottas would be able to challenge his team mate for the title.
"If he can step up and challenge Lewis he has his place among the greatest drivers in Formula 1," he said. "If he doesn't he's going to know it and there is no excuse."
Wolff warned that the Finn would need to hit the ground running. He said that Bottas wouldn't be able to afford the sort of mid-season slump he suffered in 2017.
"He recovered at the end of the season and he is a Finn with a strong never-give-up mentality," he said. "Valtteri will improve his weaknesses and continue to work on his strengths.
"I expect him to come back strong with all he learning the has done during the season," he added. "I have no doubt we will see a better Valtteri in 2018.
"He's the first one who wants to prove it to himself," Wolff continued. "He knows the deficits he had during the season and he knows where he had advantages."
Wolff recruited Bottas from Williams at short notice last winter. It came when Mercedes was reeling from Nico Rosberg's abrupt retirement after winning the 2016 title.
A former shareholder at Williams before his own move to Mercedes, Wolff was always confident optimistic about his driver's ability.
"I've known [Valtteri] for ten years," he recalled. "Ten years ago a little kid showed up in the winter in my office with a little pullover, no jacket, no father with him. He has a super-strong will, an iron will and character.
Wolff admitted that it was always going to be tough for Bottas to shine when paired up "against the best Formula 1 driver of the current day and age."
But he said that Bottas wouldn't resort to the sort of 'mind games' that were seen between Hamilton and Rosberg in previous years.
"That's not at all Valtteri's style," he insisted. "Valtteri wants to do it on the track in the best possible way.
"What he wants is to be benchmarked against a four-time world champion. He's brutally honest with himself."
Despite claiming four pole positions and three race wins in his maiden season at Mercedes, Bottas has been criticised by the likes of Jacques Villeneuve who thinks Mercedes should dump the Finn and sign up Pascal Wehrlein.
"I would rather choose Wehrlein," Villeneuve stated unequivocally.
“We like working with Valtteri and with Lewis," disagreed Wolff. "The two fit well together. They have a good dynamic in the team and see no reason to change it."