Max Verstappen believes Honda's progress with its engine is allowing Red Bull to test the durability of its own parts of its Formula 1 car more than with Renault.
Red Bull switched to Honda power for 2019 after 12 seasons partnered with Renault.
That relationship had gone sour as Red Bull's quartet of titles with Renault from 2010-13 gave way to five years of difficulty in the V6 turbo-hybrid era.
Honda has powered Verstappen to two wins so far in 2019 and had an exemplary reliability record, but the 21-year-old says that progress has also had an additional benefit for Red Bull.
"Yes we did have mechanical failures from the car and not the power unit last year, but they also came because we never had the reliability to test up to the limit," said Verstappen.
"Honda is spending so much time on the dyno and then we also find out our limits from the parts on the car, so we never had that before.
"You never had an idea if your car was strong enough or not and you only found that out from retiring, so the whole preparation before you get into a season is so much better.
"The car and the power unit are very reliable."
Verstappen has completed every grand prix this season and not finished lower than fifth, something no other driver has managed this year.
"Everything is open, we fully work together and we try to help them, they try to help us in how to do things better, so we are fully committed to each other," said Verstappen's of Red Bull's relationship with Honda.
"They are winners, we are winners, we all want to win together, so we want to always get the best out of it."
Red Bull trails second-placed Ferrari by 44 points in the constructors' championship despite Verstappen being third in the drivers' contest.
That is because Pierre Gasly is struggling in the second Red Bull and only has 63 points to Verstappen's 181.
But Verstappen is not sure Red Bull has truly overtaken Ferrari as the second-best team in F1 at the moment, despite impressive form in the last few grands prix.
"We just seem to execute the weekend better than them and bring the results back," said Verstappen.
"But they are still very fast, some tracks a bit faster than other tracks - with longer straights of course they seem very dominant.
"It is still not very clear where we are: second or third.
"One thing is for sure, Mercedes is still ahead and that is what we have to target."