Verstappen insists Renault "on top" of engine problems

Verstappen's RB13 had to spend some time in the pits during Wednesday track running for an engine change - and then brought out the red flags with minutes to go in the day, crawling to a halt at the very end of a full-on race simulation.

Reliability problems for the Renault power unit have been a recurring theme of pre-season testing so far, with the marque's works team and Red Bull's sister outfit Toro Rosso also affected.

Verstappen said Wednesday's race simulation stoppage was likely down to a MGU-K issue - and has backed Renault to solve the problem.

"We were two laps short of a race distance. Got a lot of data," Verstappen said.

"Unfortunately we had to stop, similar issues that made us stop this morning - but I’m quite confident, because the Renault boys already have some plans to change that for Melbourne anyway, so it should be all right.

"They are on top of it now. We have solutions in place for the future."

The stoppage aside, Verstappen said the race run left a "very positive" impression. "[It was] good. Long. You are on your own and is pretty boring.

"I think everything felt well, the car was behaving pretty well with degradation, pretty smooth."

Asked whether the RB13 was now good enough to be winning races, Verstappen said: "The good thing is that nobody has two seconds in their pocket. We’ll see.

"It’s really difficult to say because you don’t know how much fuel the other guys are running and the cars are still pretty new so you’re doing a lot of set-up changes and suddenly you find the right one.

"We haven’t tested all the available options in terms of setting up the car - but so far everything is going pretty well."

Additional reporting by Erwin Jaeggi