Esteban Ocon beat Max Verstappen to the F3 European title in 2014, so he found it “difficult to swallow” when Verstappen was promoted to F1.
When he debuted for Toro Rosso in 2015 at just 17 years old, Verstappen became the youngest F1 driver of all time.
But the year before that Ocon had beaten him to the F3 European title, yet the Frenchman had to wait until the 2016 Belgian Grand Prix to make his debut.
Both drivers are part of the F1 grid for 2020.
“I think the first time I raced with Max Verstappen was in 2010,” he wrote on the F1 website.
“It was a tough year for me transitioning into international racing. Karting is very tough anyway. I was alone with my dad pretty much fighting the big teams.
“Max and I were always quite close on track and sometimes it came too close! In 2011 we were fighting for the 2011 world series championship and he won in the end.
“I remember a race in Italy I came out on top, but me and him were a long way ahead of the rest. It was a rivalry which started then, and it soon became even bigger.”
Ocon took the F3 European title in 2014 after nine race wins, but Verstappen took ten that year, including a run of six consecutive wins despite finishing P3 in the standings.
It was enough though to earn the Dutchman a spot in F1 for 2015, and Ocon admitted that Verstappen earning a promotion before him was “difficult to swallow”.
“After a few races, the competitive rivalry returned,” Ocon explained. “Max started to become strong and he was challenging me for wins and suddenly he was the guy to beat.
“We had a thing called the ‘triple record’ where you would win all the races in a weekend.
“He [Verstappen] did that [twice – at Spa and the Norisring] and then I did it in Moscow at the following round!
“We were fighting to get that all the time. In that Moscow race he came close to beating me and we banged wheels a couple of times, just like the old karting days.
“I won the title in Formula 3 but the tough moment for me was that Max had signed a deal to race Formula 1. Well done to him, definitely, but when I saw the news it was difficult to swallow.
“He was third in the championship; I was winning, and I didn’t have a seat in any category at that time.
“I did a few tests in GP2, but there was nothing really confirmed. The Lotus F1 junior programme had difficulties at the time and I wasn’t going anywhere, so it was quite a challenging moment.
“But I used that as motivation. I knew I had to work hard and keep on top of the junior categories if I was to make it to Formula 1.
“It was my ultimate target; not necessarily wanting to face Max again, but rather joining him in Formula 1.”