Pietro Fittipaldi's attention moved from Formula 1 to Le Mans-style sports cars last weekend after he was overlooked for the full Haas race seat for 2022.
The grandson of F1 legend Emerson Fittipaldi is Haas' fully-fledged reserve driver, but the small American team instead opted for Kevin Magnussen's experience following the ousting of Russian driver Nikita Mazepin.
"As a driver, I was obviously disappointed because it was really close," Fittipaldi, 25, told France's Auto Hebdo at the European Le Mans race at Paul Ricard.
"When Gunther called me, he said it was between Kevin and me. In the end, the team favoured experience because they needed it in the team's situation.
"I understand that, but I also know what I could have done because I was always very strong in the tests and in the sessions that I was able to do, and I know that we could have kept our promises.
"It would have been huge. We had a lot of support from Brazil, and also from the United States because I was born in Miami, but I wouldn't say the chapter is closed," Fittipaldi insists.
For now, then, Fittipaldi will continue to be on stand-by for Haas whilst also focusing on the European Le Mans series.
"We have to keep working and it will be very important to have great results here this year, at Le Mans too, and then see what the future holds," he said.