Carlos Sainz has lamented Toro Rosso's lack of running on the back of niggling issues associated with Renault's power unit.
Sainz lost precious track time yesterday when he stopped early because of an engine problem, with more woes affecting Dany Kvyat this morning and Renault changing the STR12's power unit.
"We knew it was going be a tough first test," said Sainz.
"Especially because the engine is completely new. It's a bit like nearly a start from zero from there, so it was obviously not gonna be easy.
"But of course we would have liked to do some more laps these last couple of days, but we need to give them time.
"The whole team will tell you that we would have liked to do more laps and to complete a bigger part of the programme.
"They have done a fully new engine that they are predicting a good step on power, so as long as this power is delivered in the first race, I'm not going to complain at all."
The Spanish driver is obviously looking for a better second week of pre-season testing.
"I think now the main focus is to improve the reliability. I'm not going to apply any kind of pressure or anything, because they already know that we need to keep working on that and start adding some laps to our lap count."
GALLERY: F1 drivers' wives and girlfriends
Keep up to date with all the F1 news via Facebook and Twitter
