Nasr said earlier this year that he was "100 percent convinced" that his chassis was handling worse than that of teammate Marcus Ericsson after the Swede outqualified him in Australia, Bahrain and China.

The Brazilian got a new chassis for the Russian Grand Prix, but team boss Monisha Kaltenborn says the Swiss team could find nothing wrong with the old one after a thorough analysis.

She said building the third chassis was not a big issue for the team, as it was already planned to be introduced around that time.

"The third chassis was planned already, so it was nothing we had to do because the driver said it," Kaltenborn told Motorsport.com.

"We had actually planned to bring it about that time. We discussed it with the driver. We actually told him where we might see something, and where we don't, but at the end of the day you have to see what your driver is saying because he's sitting in the car.

"We have done an analysis and we have not seen anything."

When asked if the team would use the old chassis again, she said: "It is very much possible because there is nothing on it."

Nasr has been outqualified twice in three races since the new chassis was introduced, although his engine blew up in qualifying in Monaco.

The duo made contact with each other in the previous race in Monaco, a crash that Kaltenborn labelled as "unacceptable".

Interview by Oleg Karpov