Toro Rosso duo predict tough weekend

The German driver, who was unable to test last week at Barcelona after teammate Sebastien Bourdais destroyed their car in a crash, finished down in 18th position, 1.7 seconds off the pace.

Vettel reckons there is still more speed to be extracted from the car, but the Toro Rosso driver is convinced the Italian squad are in for a tough weekend.

"It was quite a productive day but there is still a lot of room for improvement," said Vettel.

"We identified various areas to work on and the good thing is that in the afternoon we made progress with that and moved on from the morning, even if from the outside, you cannot see the improvement in terms of pace.

"I am not sure where we are in terms of the order, but this is definitely going to be a tough weekend. But of course we will continue working tomorrow and keep fighting."

Bourdais also admitted the team were not strong enough to fight in the midfield this weekend, although he still believes they could get into Q2 tomorrow.

"The conditions are very different to our last test here in February and our main job today was to try and make the most of the package we have got," the Frenchman, 19th today, said.

"Our potential is not strong enough to be a midfield contender at the moment, as everyone has made big steps forward with their newer cars.

"The wind moved around from the morning to the afternoon, affecting the balance of the car. But overall, I think we made a step forward from the morning.

"It's going to be tough and now we will see where we are in qualifying when we take the fuel out, which makes the car a different animal. If things go well, maybe we can get through to Q2."