McLaren's Zak Brown says the fact that Stoffel Vandoorne and Fernando Alonso did not always have the same equipment led to the odd large performance gap between the two drivers.
Early on in 2017, the Belgian driver found himself on the receiving end of Honda's engine woes. But as reliability improved, as well as his own approach to his driving, Vandoorne was generally on a par with his illustrious team mate.
Brown says he was impressed by how the 25-year-old bit the bullet during the difficult times and raised his game thereafter.
"It was a very difficult start for him with our reliability issues," Brown told GPUpdate.net.
"He's a rookie, he was going to a lot of tracks for the first time.
"Fernando [Alonso] has the benefit of 15 or 16 years [of being in Formula 1], so if he had an issue and it was kind of 'you've got five laps to do it', he could draw on 15 years' experience.
"Stoffel would miss some sessions, having never been to the track before, and he's got five laps to do it, oh and by the way your team-mate is one of the best drivers in the world.
"If you look at the pressure and circumstances, his attitude was great, his speed is getting better and better, he's very close to Fernando now."
The McLaren boss also underlined the fact that during the team's ongoing development program, when updates and components were scarce, Alonso was given priority.
"They've not always had the same equipment," explains the American.
"We run both cars identically but there have been times that you have only one development piece, so nine out of 10 times you give that to the more experienced driver.
"There were some races where the gap may have looked larger than they were but that was a car gap more than a driver gap, so I'm very happy with him."