Kubica realistic on Renault's form

"I think we need to stay realistic at this stage of the season because the top three teams are still pushing very hard to develop their cars, while we only brought a small upgrade here," said Kubica after qualifying eighth ahead of tomorrow's Singapore Grand Prix.

Renault was expected to enjoy a strong outing at the Marina Bay circuit due to the similar characteristics to Monaco, where Kubica shone all weekend.

But the French squad has not brought significant updates to Singapore, while some rivals are still pushing hard with their development.

"Mercedes and Williams have also been at a very similar pace to us for several races, so we knew we would be fighting in the second half of the top ten today and that meant it was difficult to achieve much more than P8," added the Pole.

"The car is lacking overall grip, and sliding front and rear, but I was quite happy with my lap. Our timing meant we only did one timed lap in Q3, so it was all or nothing, and I think I got nearly all the potential out of the car."

Team-mate Vitaly Petrov endured a disappointing day after damaging his car when he spun during Q2, the Russian unable to move into the top-ten shootout.

"Looking at the times, it would have been possible for me to get into Q3 today, but I made a mistake on my first run in Q2," he said. "I had gone through Q1 on the prime tyres, and was pushing hard on the options when I went too deep on braking for turn five, lost control of the car and hit the wall with the right rear wheel.

"The corner was still damp from the rain this afternoon, like it has been most of the weekend, and it just caught me out: it was my mistake. I know that it's going to be a tough race tomorrow, especially because overtaking is so difficult here in Singapore."