The Red Bull driver has grown more frustrated by its current engine partner this season and has been increasingly critical in public since his team confirmed it would switch to Honda for next year.

Honda is introducing an upgrade in Russia this weekend that some sources have tipped to move it above Renault in pure horsepower for the first time.

Asked about that possibility, Verstappen said: “Well, let's say I'm very confident that at the start of the season we will not be worse than Renault.

“We will always be in the same or a better position.”

He added: “I hope that it [the upgrade in Sochi] will already be a good step.

“I know the steps they are making up until the beginning of next season so it all looks very promising.”

Honda’s progress with Red Bull’s junior team Toro Rosso this season has been evident in its improved performance and stronger reliability record.

While its upgrades this weekend mean grid penalties for both drivers, Verstappen has previously pointed out that Honda’s increased use of engine components this season is misleading because it has been tactical in how it has changed parts.

However, current Renault drivers Carlos Sainz and Nico Hulkenberg disagreed with Verstappen’s early assessment of the ’19 engine pecking order.

“I don’t think so, but we’ll see,” said Hulkenberg. “Next year there are a few good things coming so I think we’ll make some good progress.”

Though Verstappen is certain Honda can match or surpass Renault, Sainz – who will stick with Renault power when he moves to McLaren – said: “I think ‘sure’ in F1 is a very particular word to say.

“I still have faith in Renault, obviously I’m sticking to that engine for next year, in another team.

“We just need to trust, and that’s it.”

Verstappen will join his future engine partner Honda at the back of the grid in Russia, after revealing on Thursday that Red Bull’s move to a fresh Spec B engine is because of a reliability concern for the Spec C at future races.

Though the outspoken Dutchman has increased his criticism of Renault recently, he is also investing a lot of time into seriously studying Honda ahead of 2019.

Verstappen expects to visit the manufacturer’s Sakura research and development facility later this year or early in 2019 and is leaning heavily on his team for information in the meantime.

“I always ask questions about a lot of stuff - driveability, downshifting, energy deployment, all these kinds of things,” he said.

“Of course the team is really busy with it now and just analysing everything.

“It looks promising. They are working really hard to get the gains and they are spending a lot of money on the whole project, which is very good.”

Additional reporting by Adam Cooper