By his own admittance, Valtteri Bottas' 2018 campaign fell well short of expectations, but former F1 driver Mika Salo believes his fellow Finn is being too hard on himself.

Despite driving for a team that garnered 11 wins this season thanks to Lewis Hamilton, Bottas concluded his season without ever standing on the top step of the podium, a feat he achieved three times in 2017.

Mercedes boss Toto Wolff fears the misfortune that befell the 29-year-old this year and the necessity to confine him to a support role in the latter part of the season may have taken their toll on Bottas' mentally.

"At least he has identified what were the weak points for him and will work in the winter so that they are not there next year," Salo told Finland's MTV.

"Valtteri has no choice but to reset completely and start again next year.

"Pretty much everything went wrong this year," he added.

"Baku was really bad. If not for what happened he would have led the championship and who knows how the season would have gone after that."

Salo said Baku is just one example of how 2018 was not all Bottas' fault.

"There were so many little things that were just bad luck, not anything that Valtteri did badly. But they surely affected him on the mental side pretty badly," he said.

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