Scott Speed believes Sebastian Vettel replaced him at Toro Rosso in 2007 because he was regarded as a "golden child" in the Red Bull development programme.
American Speed raced in F1 for one-and-a-half years, making his debut in 2006 at the season-opening Bahrain Grand Prix.
He never scored any points for Toro Rosso with reliability issues hampering his progress and he was ultimately replaced after the 2007 European Grand Prix by Vettel.
In an interview for the Beyond The Grid podcast, Speed believes he was just as quick as Vettel, pointing to immediate results when the German took over.
He said: "They called and said they were gonna put Vettel in the car. I thought 'awesome' because at that point Vettel was the golden child. I was thinking 'great let's get him in that thing' and see what he does.
"Sure enough, Vettel qualified 19th (in the Hungarian Grand Prix). I don't remember where he raced but it wasn't amazing at all."
The Californian native would never race in Formula 1 again following his exit from Toro Rosso, despite having talks with other teams including Williams.
He endured a frosty relationship with team principal Franz Tost, who remains in charge of AlphaTauri - the successor to Toro Rosso. In the end, the two parties split with Vettel taking over for the remainder of the season.
The rest is history as they say, with Vettel earning a first race win a year later before going on to win four world titles with the senior Red Bull team.
Even though his F1 career was cut shorter than intended, Speed says he is happy with what he achieved in his career.
"I thought I can pack my bag and go wherever I want," he said. "I know that I'm elite. Maybe I'm not the best but I'm so far beyond what I thought I'd achieve as a kid. I was super happy.
"Then came opportunities, the meeting with Williams and the chance to race other stuff. But, ultimately I said 'Man I want to go home. Can we race NASCAR?'"
Since leaving F1, Speed has raced in IndyCar, Formula E, and the now-defunct A1GP.