Red Bull team boss Christian Horner believes Ferrari's engine is now leading the way in terms of performance in Formula 1 and says the improvement of its two customer teams, Haas and Sauber, is evidence of that.
The improvements Ferrari has made to its power unit this season have been credited with its ability to compete with Mercedes – it currently leads both Drivers' and Constructors' Championships.
Although the two power units are reportedly on a par, Horner believes Ferrari's is now the "benchmark" in Formula 1.
"I think it’s setting the benchmark now," he said. "Haas and Sauber as well having made good gains. We’re [Renault-powered teams] probably further outside."
Red Bull struggled with straight-line speed during last weekend's British Grand Prix, and whilst some of that is down to its high-downforce set-up, Horner still insists their Renault unit is lacking in horsepower but is hopeful the team's switch the Honda for 2019 will remedy that deficit.
"You can see the situation between the engines is very similar at the moment, and it is all about the potential development. This weekend [Silverstone] has been a very tough weekend for Renault.
"It just very clearly defines where the level is at. You can’t hide behind the statistics we saw. There is a gap to fill and hopefully in Honda we have a lot of belief what they have coming in the pipeline."