At a time even Mercedes felt it was alright to 'unleash the best', Robert Kubica was still trundling round in the Williams FW42, running the various aero tests that the world champions were running three days ago.

At one stage, Lewis Hamilton had to take a detour across the generous run-off at the final chicane after encountering the Williams while he was on his own hot lap on the C4 tyres.

Speaking at the end of a morning in which he put 48 laps on the Grove outfit's contender, posting a best time 3.9s off Alexander Albon's best, veteran Robert Kubica admitted that his team faces a struggle.

"You can get a feel of it, it's not like the car is completely off," he replied, when asked what he had learned from his morning in the car.

I think there's still something to put on the car, probably not a lot," he continued, "but for sure there are things that were compromised.

"It's not right that I talk about them," he quickly added, mirroring Claire Williams desire not to do the team's dirty washing in public, "as I said before I'm here for driving, so I have to concentrate on this.

"Finally I have a car," he smiled, "so hopefully next week we can concentrate on preparing better for the first race, because it's close.

"It doesn't feel like day four of testing, it felt like day one," he admitted. "I got the opportunity for 12 laps to get a feel for the car, which is of course limiting. At least all sorts of stuff we achieved, not all, it wasn't an easy morning.

"I've been here since last Friday. I've never waited so long to get 12 - 14 laps, that I could drive my own pace. You just prepare what you can.

"It wasn't nice days for all the team, but finally we got the car. In the end the team did a good job to build it up as quick as possible. Of course there are some compromises, but finally we got the car, so we can concentrate on our job, and look forward to next week."

Asked if the FW42 is a step forward compared to its ill-fated predecessor, he replied: "In some ways it is a step forward... for the others, not necessarily. The question is if we have done a bigger step forward and smaller backwards, because of regulations. Then it's a question of balancing.

"At this stage it's not correct to talk about the performance of the car, or feelings," he concluded. "We will see next weekend."

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