Toro Rosso’s car drew attention at its launch on Sunday, particularly for some design features it has in common with the latest Mercedes, but the team had a troubled first day that Sainz put down to “a little bit of everything”.

While the Spaniard managed 51 laps, he was amazed at the mileage achieved by other teams, with Mercedes (152), Ferrari (128) and Williams (103) all surpassing 100 laps.

“We were planning to do more laps than we did,” Sainz told reporters in the Barcelona paddock.

“We found a few issues around the car which we were improvising and solving through the day, but we knew these issues could appear.

“What I don’t understand is how the others did 120-150 laps, the top teams. But the first days of testing are always tough, you cannot really compare yourself to Mercedes and Ferrari.”

100-lap target

Sainz said the team’s problems were mixed, with the chassis needing some work to improve its reliability.

“The first day of testing, both the engine and the chassis have to work together,” he said. “You keep finding little problems here or there that slow down your running – it’s typical. This time it was a bit more chassis related but it was a bit of everything.

“Hopefully [team-mate Daniil Kvyat] does a lot more laps than me today and then I do a lot more laps than him tomorrow and we keep adding to that lap count and we get close to the 100-lap mark.

“That should be our target for the rest of testing.”

Additional reporting by Lawrence Barretto