Toro Rosso starts F1 season with confidence soaring, boss Tost says

The STR11 emerged as a reliable car, completing a total of 3,034 miles over the eight days of running at Barcelona's Circuit de Catalunya, second only to Mercedes' tally of 3,742.

Tost concedes he was surprised at what unfolded, considering its deal with Ferrari to take a 2015 power unit was only concluded late last year, giving his staff little time to integrate it into the car.

Assessing the two weeks in Spain, Tost said: "We've had the best preparation as long as Toro Rosso has existed.

"We've done so many laps and collected so much data, and from the driver point of view, the engineering side, the team itself, we have reached quite a good level.

"The target is fifth place in the constructors' championship, and if we want to achieve this then we have to perform well and score points in all the races.

"Sometimes, hopefully, we will be able to come up with a highlight, which will be a position in the top five.

"But for now, our level of confidence and optimism is higher than ahead of any other season."

Tost admits the reliability was a "a positive surprise", one which has provided a platform on which the team can build, particularly early in the season.

"To be honest we didn't expect to be in a position to do so many laps after the last two or three months because we worked 24 hours [per day] to finish the car in time," said Tost.

"The first time I saw our gearbox and how it is fitted into the car, I thought 'Jesus Christ! How can we check the reliability?' because you don't see all the cables, lines and tubes any more. Everything is covered.

"Fortunately, it works so far. Now we have to prove it in the races, but from a reliability point of view, I am quite happy."

Tost's confidence extends to the fact he fully expects both Max Verstappen and Carlos Sainz Jr to be regular, top-10 contenders in qualifying.

"It's difficult to assess [where we are] because you don't know how much fuel the others had in the car," he said.

"But generally speaking I expect both cars to be in [the top 10] because I'm quite optimistic with adding our performance.

"The car so far behaves quite good, and from the reliability point of view we have never been at such a high level because we have finished a lot of laps."