Renault reliability has made 2015 a write-off for Red Bull - Christian Horner

Luca Martini/Sutton Images

The engine penalties looming over Red Bull has resulted in team boss Christian Horner labelling this season a write-off after just the fifth round.

Engine supplier Renault finished its first race weekend without a major engine failure in Spain, but the two Red Bull drivers and Toro Rosso's Max Verstappen are still just one engine change away from a grid penalty this season. Red Bull has not held back in criticising Renault this year and Horner made no exception following the Spanish Grand Prix as he urged the French manufacturer to focus on performance and forget about trying to avoid penalties.

"We are so far on the back foot with reliability anyway that, to be honest, this year is pretty much a write-off," Horner said. "You just have to go for it, even if they end up using 20 engines, it would be better to learn and make progress for next year. It would be far easier to make a fast engine reliable than to make a reliable car fast, so our philosophy has been to push performance.

"I think it is positive Renault got four engines to the finish without any white smoke, so it is step forward from previous races. Focus desperately needs to turn to performance before too long. I think they know what the deficit is. The question is how are they going to make that up. They have things in the pipeline and things for later in the year but it is all a work in progress. From a team point of view we want it as soon as possible, obviously Renault is nervous about reliability so it will certainly be second-half of the year before we see anything significant."

Asked if he was concerned about junior team Toro Rosso outperforming Red Bull in qualifying this weekend, Horner added: "I think it is very easy to take snapshots. You have to look at the season. Don't take anything away from Toro Rosso, they are doing a good job. They are not happy with where they are, if they had 80-90BHP more they would be in a better position, as would we."