On this day in 1992, Ayrton Senna put himself behind the wheel of a Team Penske IndyCar at Firebird Raceway, in Arizona.
The Brazilian had just wrapped up a disappointing F1 season in which he had only finished fourth in the championship. But it was Honda's decision to leave the sport that had Senna questioning his future.
Emerson Fittipaldi encouraged his good friend to sample his Penske ride, which Senna readily accepted.
He ultimately didn't make the move to the US-based series, but the secret test yielded an impressive performance as he beat Fittipaldi's best lap time by half a second!
What could have Senna accomplished had he raced in IndyCar? We'll never know...