However, after stepping up to the main team Verstappen secured a spectacular maiden win at the 2016 Spanish Grand Prix, and has remained with Red Bull ever since.
Sainz on the other hand has jumped from team-to-team racing with Renault, McLaren and now Ferrari.
Verstappen leaves Sainz without a seat
In a recent interview for the Nude Project Podcast Sainz revealed how Verstappen’s early career success nearly stopped him from entering F1.
"I have a good career in karting, I stand out at 14-15 years old, always in the top 3 of championships, from then on, Red Bull tests me for their young drivers academy," he said.
"If you are not part of one of their academy, Ferrari or McLaren, your options of reaching F1 are remote or you have a father with a lot of money because the jump from karts to formulas was economically very difficult, fortunately Red Bull signed me and sponsored me.”
"I was doing very well, I moved up categories and in 2014 they told me: 'Either you win or you don't move up to F1, depending on how you perform.'
"In the Bull Series, I started to win many races and was close to winning the Bull Series, which was the requirement to get to F1, Red Bull signs Max Verstappen and they raise him to what would be my potential seat, so I do what they ask me at Red Bull and out of nowhere I am left without a seat anyway," Sainz added.
"I won the championship and luckily another F1 seat opened up that in the end could have ended up being for me, but it was something that I didn't know and that Red Bull hadn't contemplated it either.”