Nico Rosberg says Valtteri Bottas “needs to step it up” against Mercedes teammate Lewis Hamilton if he is to have any chance of winning the Formula 1 world championship. 

Bottas beat Hamilton to pole position at the Eifel Grand Prix and looked to be in control of the early stages of the race, having fended off the Briton’s attack into Turn 1 to hold the lead with some punchy driving. 

But Bottas’ race fell apart when he made a critical error by locking-up and running wide into Turn 1, opening the door for Hamilton to pass him around the outside of the following corner and snatch the lead. 

Bottas ultimately retired from the race with engine trouble, while Hamilton went on to claim a record-equalling 91st career victory to stretch his advantage at the top of the championship to 69 points with six races to go.

Rosberg, who pipped Hamilton to the 2016 crown, was impressed by Bottas’ bold fightback against Hamilton at the start of the race but says the Finn must eradicate his errors if he is to give Hamilton a proper fight. 

“Lewis is ahead going into the corner, and then Valtteri does an amazing job with sticking it out on the outside, and putting his foot down even when he’s off the track there, to take the position back,” Rosberg said on Sky Sports F1. 

“It was awesome driving. I think I tried that like six times in my time against Lewis and I always lost out. I mean you don’t go around the outside of Lewis Hamilton. 

“Then a couple of laps later Valtteri does make that mistake that he can’t allow himself to make against Hamilton, you have to keep it perfect.

“Bottas needs to step it up. He is not challenging Lewis hard enough.”

Earlier in the weekend, Rosberg also discussed Toto Wolff’s rumoured departure from his current role at Mercedes, saying it could result in “a really bad turn of events” for the team.

Rosberg believes Wolff’s decision is having a direct impact on Hamilton’s own future amid delays to the six-time world champion’s expected contract renewal at the German manufacturer. 

"I do think it matters," Rosberg explained. "Because Lewis is very convinced that Toto is an integral part of the success of that team, which is true, because Toto absolutely is. And it's not guaranteed that if Toto goes and there is a new leader that the stability remains.

"And also if Toto goes it could potentially be a spiralling effect, so that many of the team leaders in the leading positions say, 'OK it's the end of the an era, Toto's going, I loved to work with him, let's also move on to something new'. That could be a really bad turn of events for the team."