AlphaTauri announced on Saturday that 2019 Formula 2 champion de Vries will be joining the team for next year, replacing the Alpine-bound Pierre Gasly as Yuki Tsunoda's teammate.
De Vries made his F1 debut as a late stand-in for Alex Albon at Williams in the Italian Grand Prix last month, scoring two points with a run to ninth place.
It helped accelerate talks with AlphaTauri, which had initially set its sights on IndyCar driver Colton Herta to replace Gasly, and ultimately paved the way for a deal being signed for 2023.
Speaking on Saturday at Suzuka, Verstappen revealed that he had dinner with de Vries after the Monza weekend and encouraged him to give Marko a call to discuss options for next year.
"We had a dinner the day after Monza, and I told him, just give [Marko] a call, you never know what happens," Verstappen said when asked by Motorsport.com if he'd put in a good word for de Vries at Red Bull.
"It was also the right time to call him. Helmut is probably still excited on a Monday from the race on a Sunday. It worked out well, and I'm very happy for him."
The chance for de Vries comes after a meandering racing career to date that saw him win titles in F2 and Formula E, as well as racing in the World Endurance Championship and even considering a switch to IndyCar as recently as this May.
De Vries has served as Mercedes' F1 reserve driver for the past two seasons, appearing for Mercedes, Williams and Aston Martin in FP1 sessions this year as a young driver.
Verstappen said de Vries had been "pushing hard for it for a long time" and that it was "incredible" for him to finally get a shot in F1 full-time.
He felt the run to ninth at Monza meant there was "no real discussion anymore" about his credentials for a race seat in F1, and that Marko would have been open to taking the chance.
"Helmut is a guy when he likes something, he's daring enough to then put him in the car, whereas maybe other teams are a bit more careful," said Verstappen.
"That's great news. We are good friends as well."
