Renault F1 teams don't expect repeat of 2014 testing problems

At Jerez last year, Renault suffered a hugely disappointing first outing for its new turbo V6 engine, with it being troubled by both poor reliability and a lack of performance.

But after a refocus of Renault's F1 efforts and a overhaul of its power unit this winter, Red Bull and Toro Rosso chitefs say all indications are that the manufacturer is on course to enjoy a much better pre-season.

Toro Rosso team principal Franz Tost said on Saturday: "Renault has done a step forward, this is without any doubt.

"But to do a step forward is one thing: it now depends on what step forwards Mercedes has made.

"But I am quite positive about the work from Renault - because on Wednesday we were the first team out on track, during a filming day, and we did 96km without any problems.

"This was a big step forward and I hope we can do a good test here. We trust in the work of Renault and the rest we will see."

Toro Rosso technical director James Key added: "They [Renault] are certainly in much better shape now than they were last year.

"They went through a tough time last year but they have recovered extremely well, so we will see what we can do."

Red Bull chief designer Rob Marshall also believes that his team will have a calmer time during the build-up to the campaign - having endured a spate of reliability dramas this time last year.

"I'm hoping for a much more ordered pre-season," he said. "There should be less drama.

"The engine's much more known to us, so unless there's some big drama around the corner, I hope we'll have a more sensible time."