Following weeks of negotiations to find a replacement for Rosberg, Mercedes and Bottas finally signed their contract on Monday to complete his move from Williams.

And Lauda has no doubts that the German car manufacturer has got the right man, and that the Finn will be just as strong as his predecessor.

"Bottas is the best man," Lauda told German broadcaster RTL. "I believe he can drive similarly as fast as Nico. This is why we start the new season with him and Hamilton.

"We looked for a driver who fits our team. Until now we always had two top drivers who were able to fight for the world championship. Nico and Lewis were a fine example of that, because they were fighting head-to-head.

"Sometimes one was in front, sometimes the other. In the last three years we won everything there was to win. And this is why we decided to go with Bottas, as he brings experience and speed to the team."

"He is a calm Finn and I like that about him. He doesn't talk a lot but is a hard worker. Toto and I have known him for years. I think he fits really well into the team."

No team orders

Lauda also made it clear that Bottas would be free to challenge Hamilton as hard as he wanted, as Mercedes guns for its fourth consecutive F1 title.

"As always: both drivers can push as much as they want, completely free. This never has changed at Mercedes and it won't change in the future.

"We talked to Lewis and explained to him that Bottas will be driving alongside him. Lewis doesn't have an issue with that and neither does Bottas. I think we can go calmly into the season with these two drivers."

Relaxed team

Lauda added that he felt more relaxed too, with the uncertainty that the Formula 1 team faced when Rosberg quit at the end of last year having passed now that it has managed to sign Bottas.

"The commotion after we lost Nico has gone completely," said Lauda in an interview with German broadcaster RTL. "I'm very relaxed now because I believe with Bottas we again have an equal driver pairing like last year."

Additional reporting by Stefan Ehlen