Max Verstappen says Honda have done everything asked of them by Red Bull in pre-season testing, the Dutchman claiming their performance has put to bed any lingering doubts over the Japanese marque's ability to step up to the team's level in 2019.
Red Bull ended testing with two frustrating days of limited lap time.
This was not the engine blowouts of old seen in the McLaren-Honda, however, instead Red Bull's troubles stemmed from Pierre Gasly's crash on Thursday, which in turn left Verstappen nursing a patchwork RB15 through the final day.
A gearbox issue limited the Dutchman to 29 laps and denied him the chance of a 'glory run', but it did not dim his positivity over the test as a whole.
"So far I'm really happy with the cooperation between Red Bull and Honda," he said.
"They are really working hard and very focused and calm – everything you ask from them, they are working back at the factory to improve so, so far, I'm really happy with it.
"It was always a question mark for many people, how it was going to perform, but we saw from the dyno testing and then again here on track, it was very reliable and did exactly what I wanted, so I'm very happy."
The limited final-day effort meant Verstappen's best time of 1:17.709 was a second and a half down on Sebastian Vettel and Lewis Hamilton who the Dutchman has been tipped to battle for honours in 2019.
On Mercedes' and Ferrari's pace, he added: "I'm not too worried about it.
"For sure, they are very quick, but I'm happy with what we have done so far.
"Also the long-run pace is very promising.
"Of course Melbourne is a different track again, so different temperatures, and will be again about finding good set-up in the car. It's a long season.
"In general, compared to them, we've been good in terms of pre-season testing. They always do a lot of laps, but from what I've felt on the car it is promising."