The 21-year-old is considered favourite to move up from Red Bull's sister team Racing Bulls to replace Yuki Tsunoda alongside Verstappen in 2026.
Reports suggest Red Bull are due to confirm the identity of Verstappen's new teammate next week.
Aware of the magnitude of the challenge that might await him, the Frenchman nonetheless sees a partnership with Verstappen as a decisive step in his career.
"Against my teammates, I've always been stronger," but "alongside the best in the world, it's an incredible opportunity to learn", he told AFP in Doha ahead of this weekend's Qatar Grand Prix and sprint race.
Hadjar is under no illusions of the task he could face if picked to drive Red Bull's second car alongside the four-time champion.
Asked whether he could beat the Dutchman if he were selected as a teammate, he replied with an emphatic "No".
"He's better in every aspect, he drives better, makes fewer mistakes, and he has more experience too," said Hadjar, who has impressed on his debut campaign, securing a maiden podium with third in the Dutch Grand Prix.
He sits ninth in the championship standings, having garnered 51 points.
Verstappen is still in the hunt to claim a fifth successive title with two weekends remaining. He goes into the penultimate round level with Oscar Piastri, the pair lagging 24 points behind McLaren's Lando Norris.