Red Bull motorsport advisor Helmut Marko is adamant Honda will be ahead of Renault in the engine stakes when the senior team join Toro Rosso as a partner in 2019.

The performance gains made by the Japanese manufacturer was one reason why the Milton Keynes outfit opted to take what many consider the more risky option of changing supplier after 12 years with Renault.

Another was a loss of confidence in their long-time supplier to produce a product that could compete with Mercedes and Ferrari on a regular basis.

"I'm sure we'll be ahead of Renault next year," Marko told Red Bull-owned Servus TV this week.

"Renault doesn't have the current engine package under control. They don't have the performance at the level of Mercedes or Ferrari and it also hangs on the reliability.

"We have lost faith in Renault," he continued. "The promise of Renault that we would be competitive hasn't happened. That's why we took pleasure in the alternative that was offered to us."

Something else Red Bull has regularly touted in their justification is the increased size of the operation at Honda and the increased potential as a result.

"With Honda, we have a partner who is fully committed, has the human and technical resources, and sees us as the number one team," he claimed.

"Honda will spend a lot more effort next year. They have a development centre in Sakura that nobody else can match."

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The memories of the company's failed return with McLaren continue to cloud some people's view of Red Bull's decision though, but there again the Austrian is unconcerned.

"We have a different approach with Honda than McLaren," he said.

"They more or less dictated to Honda what the engine should look like, we simply said that they should build the best engine available and then we try somehow to accommodate it in the chassis. We discuss everything together.

"[Honda] have realized that they have made mistakes. There was a change of staff and they got advice from experts," he added.

"This year's form of Toro Rosso clearly shows that things are going up."