Former Mercedes driver Valtteri Bottas believes that Lewis Hamilton's relentless ability to improve year-over-year represents the seven-time world champion's biggest strength.
Bottas shared the Mercedes outfit's garage with Hamilton for five seasons, a productive period during which the pair's working relationship never wavered and that yielded ten wins for the Finn.
But beyond his track record with the Brackley squad, Bottas revealed what he viewed as Hamilton's most impressive prime asset as a great driver.
"You know, with Lewis, what has been really impressive is that every year he’s been able to develop," said the Finn, quoted by Formula1.com.
"He’s got such a big experience in Formula 1 but still he’s been able to always learn more, become better and better.
"For sure, I’ve developed every year as a driver but so has Lewis, and it doesn’t come automatically.
"He works for it, because he knows that the competition always gets tougher."
Whether it was studying his teammate's driving on track, pouring over data and listening to Hamilton's views during debriefs, Bottas acknowledged that that he had certainly learned a lot during his five season alongside the Briton.
"I’ve definitely learned many things from him, like driving-wise, set-up-wise, lots of small things here and there," said the Alfa Romeo racing driver.
"But just it’s been impressive that he’s been able to still develop and not to get too comfortable, ever.
"He always wants more out of himself and the team around him, so that’s been the same thing every year – he keeps getting better."