Vettel not expecting easy weekend

The German, a sensational winner at Monza two weeks ago, could only manage the 13th fastest time after complaining about the handling of his Toro Rosso car.

Vettel admitted the very bumpy track surface was not making things any easier either.

"Visibility is not a problem. Some places are darker than others and it's good fun," said Vettel. "The track is very difficult, but unfortunately the surface is very bumpy which does not make life easy. It is tough and demanding for both car and driver.

"As for my car, I'm not happy yet as it feels very loose and I don't think we will have an easy time. So tonight we must work hard to improve it and hopefully make a step forward tomorrow."

Sebastien Bourdais also lamented the bumps on the track, although the Frenchman said there were no problems with the lighting.

"There are no worries about running under the lights and I even ran with a lightly smoked visor," Bourdais, 14th fastest, said. "There are hardly any shadows and you can see very well.

"It's a very nice track but unfortunately, the quick parts are the bumpiest and so we are having to run the cars quite high, which obviously reduces performance. Globally the car is not too bad and today we have been trying to find the best set-up and assess the two types of tyre."