Robert Kubica claims the only path he sees back to racing in Formula 1 again is with Williams despite their ongoing lack of competitiveness.

The Pole, who is currently the reserve and development driver at the Grove-based team, made his second practice appearance of the season at the Red Bull Ring on Friday, completing a condensed test session as the team looks for solutions to their problems.

With just four points to their name this season, thanks to Lance Stroll, Williams sit bottom of the Constructors' Championship and the timesheets at the race where Felipe Massa scored their lack position in 2014.

And asked to weigh up the positives of the current FW41 car, Kubica was pretty harsh with his response.

“Engine. Power unit,” he told ESPN, which of course, comes from Mercedes. 

When asked about the chassis itself he added: “You asked for one!? The livery is nice, colours are nice…”

That fact many don't disagree with as the team runs the famous Martini stripes at least until the end of this year, but with nothing good to say about how it drives, that highlights just how poor the Williams is.

Solutions are possibly in the pipeline before the summer break, and for Kubica, the problem is down to a lack of just one thing.

“There is only one thing which is changing the performance of the car of three seconds or two seconds per lap, its name is downforce," he claimed.

“If you have more downforce, everything becomes much easier, drivers they drive better, engineers they have more room for setup, the tyres are working better because you switch them on earlier and you have less degradation.

“There is no medicine maybe for everything, but there is a big medicine which is downforce in an F1 car.”

Still watching the team's problems from the garage hasn't dampened the enthusiasm of the 2008 Canadian GP winner to one day race for the team.

“I am only targeting to be on the grid with Williams,” Kubica said. “My target is to be in the grid and then we will see.

"Of course, realistically speaking there are not many teams I can realistically end up with or talk with.”