Aston Martin team co-owner Lawrence Stroll says he strongly believes Formula 1 should remain at 10 teams in the wake of Andretti receiving approval from the FIA to join the championship.
Andretti's bid was the only one of four applicants that made the second stage of the FIA's process to receive the green light from the governing body, but it now needs to clear "commercial discussions" with F1 before it can get on the grid.
The American team announced in January that it had teamed up with General Motors and its Cadillac brand to strengthen its case.
Its approval from the FIA followed “a robust process of due diligence during which the applicants were assessed on the sporting and technical ability, the ability of the team to raise and maintain sufficient funding to allow participation in the championship at a competitive level and the team’s experience and human resources”.
But Andretti has faced resistance from the majority of existing teams and F1 itself, with Stroll joining those ranks.
Stroll, who stepped in to save the Force India team midway through the 2018 season, after which it was renamed Racing Point and subsequently became the Aston Martin works team when Stroll's consortium purchased a 16.7% stake in the company in January 2020, said F1's current model was not in need of change.
His comments, while in line with other team representatives', are the first to have been made since the FIA approved Andretti.
"The business is on fire, F1's never been in a better place and I believe if it ain't broke, you don't need to fix it," Stroll told Sky Sports F1 at the announcement of Aston Martin's return to the Le Mans 24 Hours for 2025.
"So I'm a strong believer that it's working really well with 10 teams right now, and believe that's the way it should stay."
Stroll pointed to F1's growth in the United States - which in 2023 has three races on the calendar - as evidence of his claim that it had never been better off.
As well as those races in Miami, Las Vegas, and at the Circuit of The Americas, F1 already has an existing US team on the grid - Haas - while Williams's Logan Sargeant became the first full-time US driver on the grid since Scott Speed raced for Toro Rosso (now AlphaTauri) in 2006 and part of 2007.
Andretti, which stated its aim was to join the grid in 2025, plans to be the first F1 team to operate exclusively from a US base and also intends to field a US driver.
"There's never been more fans or spectators, the audience is the highest it's ever been," added Stroll.
"I continue to see substantial growth, particularly in the United States which is the largest consumer market in the world.
"As you know, we now have three races in the States, with our second year in Miami, we're going to Las Vegas in November. So I see tremendous growth possibilities going forward."