Robert Kubica has denied that his struggle for pace in 2019 is due to his permanent arm injuries.

Until he returned with Williams this year, the Pole sat out eight full seasons after a horror, near-fatal rallying crash.

But although they are isolated at the back of the grid, Kubica is being dominated by his rookie teammate George Russell.

"He has excellent pace and is a great talent," Kubica said of the 21-year-old rookie.

"He has great support by Mercedes and will be able to show good results in a competitive car. At the moment he has no such car," said the 34-year-old in Austria.

As for whether Kubica could also thrive in a Mercedes, the Pole did not want to answer.

"One thing I can say is that my problems at the moment have nothing to do with my supposed handicap because of my arm," he told Auto Bild.

"Monaco is a good example, where people said I would not be able to drive. The problems I have are technical, not physical. But I have to live with the prejudices that some people have," said Kubica.

One bright spot for Williams is the speed of the pit crew. In France, the mechanics performed the fastest sub two second pitstop of 2019 so far.

"At least it's something positive," said Kubica. "But when you are three minutes behind ... I think the goal is to reach the finish line faster than the others."

Kubica also dismissed the impact on Williams of the controversial debate about Pirelli's tyres.

"The tyres are not our problem," he said. "We need a faster car. Right now it doesn't matter what tyres we use."