Turns out Rihanna, A$AP Rocky and a ton of other celebs love cars that go real fast ... especially if they're speeding down the famed Strip for the Formula 1 Las Vegas Grand Prix.
The much anticipated glitzy event -- which got off to a very rocky start -- turned into a massive success ... based on the actual racing action, and the A-list talent who showed up for Saturday night's race.
RiRi and her man sat in with Team Ferrari, putting on headphones to hear the drivers during the race .