Former F1 driver Alex Zanardi doubts Mercedes newcomer Valtteri Bottas can take on his teammate Lewis Hamilton in 2017.

Finn Bottas has been drafted in to succeed the suddenly-retired Nico Rosberg, who quit the German team after winning the world championship.

Bottas is saying he can take on triple world champion Hamilton, while Mercedes team figures have said the 27-year-old is a like-for-like substitute for Rosberg.

But Zanardi, who last raced in F1 for Bottas' former team Williams in 1999, is not so sure.

"Hamilton has proved several times that he has an extra level compared to the others.

"Rosberg managed to beat him, but that was about his extra qualities," said the 50-year-old Italian, referring to the huge effort and many sacrifices made by the ultimately burned-out 31-year-old last year.

"Bottas is a very good driver, no question, but he's not a Nico," Zanardi, today a Paralympic champion in hand-cycling, is quoted by La Gazzetta dello Sport.

"For Lewis, this makes it all the easier for him to dominate the championship. Behind him I see better chances for Red Bull to chase Mercedes than Ferrari.

"I trust Daniel Ricciardo, and above all Max Verstappen, a lot," said Zanardi.

(GMM)