Lando Norris' promotion to Formula 1 was a "risk" but McLaren CEO Zak Brown knew he was ready.

The young Briton enjoyed a rapid rise after joining the British team's young driver program as a 17-year-old in 2017.

During his first F1 test in Hungary that year, he lapped faster than either race driver had managed in qualifying for the preceding Grand Prix albeit thanks to one-step softer tyres.

That, along with winning the European F3 title, earned Norris the position of reserve driver in 2018 and, after Stoffel Vandoorne's struggles, it was decided to give him his chance in a race seat.

"I think there was some risk with it, Lando being the youngest British driver," Brown admitted at the recent Autosport International event.

"He's had such a stellar career every step of the way. What really clinched it for us when he did his Free Practice 1s [in 2018], he was extremely impressive.

"Also when he did the 24 Hours of Daytona [in January 2018] with Fernando [Alonso] as his teammate, we were able to see how that went and he didn't leave anything behind.

"There was debate as to actually who was quicker! He stepped up to the plate."

But while his pace caught the eye of the McLaren chief, it was actually one moment that ultimately swung the 2019 call in his favour.

"The one for me when I went 'Yep, he's ready', was when he did his first Free Practice 1 in Formula 1 [at the 2018 Belgian GP]," Brown revealed.

"He was as relaxed as when I'd seen him on the grid of a Formula Renault race.

"He wasn't kind of having this moment of 'I'm in Fernando Alonso's car, here I am'. I think the first session maybe had even been wet and, you know, he was cool and he had the speed right away."

Also Read:

• Norris expects personal and McLaren improvement in 2020 but won't 'overhype'
• McLaren: Sainz & Norris performed 'like future world champions' in 2019
• Norris didn't think he was quick enough for F1 at the start of 2019

On Norris' teammate Carlos Sainz, the American explained why he believes the Spaniard suddenly found another gear in his F1 career having moved from Renault and left the Red Bull stable after 2018.

"Carlos has been outstanding. I think he'd been living under one-year contracts in the whole Red Bull-Toro Rosso environment, obviously [Red Bull are a] fantastic team, but they can be a bit rough on their drivers," Brown suggested.

"I think Carlos is a driver that needs to know he's got a team behind him and the next race might not be his last race, which is a little bit of the environment that is created over there [at Red Bull and Toro Rosso] sometimes."