Renault admits a Formula 1 race-winning engine won't happen in 2015

Red Bull team principal Christian Horner said Renault was in "a bit of a mess" after his outfit and Toro Rosso suffered two engine failures and a "bunch of driveability issues" in Australia.

Daniel Ricciardo finished a lapped sixth and Daniil Kvyat failed to start, while Carlos Sainz Jr was ninth and Toro Rosso team-mate Max Verstappen retired with a power unit issue.

After Ricciardo won three grands prix in 2014, Renault had hoped to halve the deficit to Formula 1's pace-setters Mercedes over the winter, but the French manufacturer has failed to deliver.

Renault F1's managing director Cyril Abiteboul told AUTOSPORT: "A race-winning engine on merit is not something that is going to happen this year, we know that.

"But to win races, it is not just the engine but also the car and the drivers."

Renault concedes that it has made shortcuts in a bid to accelerate development - and it is now paying the price.

"We have been pushing an aggressive and late development programme over the winter," said Abiteboul.

"What we have done is shortcut and bypass the important steps in engine development. That means some of the stuff you should be doing on the dyno, you end up doing on the track.

"That's not really the way forward, but it is good learning for everyone who was pushing for this strategy.

"I think it is no secret that Red Bull in particular is very aggressive in their development strategy. They try to get us to apply in the engine world what they apply in the chassis world.

"We can do a better job on the engine side but it is not something you can do in one winter."