So we're all, uh..... armchairing a street race.... which only one person witnessed? Woo!
Officially: Project Blue Book says this never happened. A Viper did not lose to any other car. It must have been a weather balloon. Question me again and I'll send the MIBs after you.
Unofficially: Hey, it's the real world and anything can happen. You never know quite WHAT you're up against with another car/driver, even if you have the chance to eyeball it. So some other car could be modified from bumper to bumper, but also the Viper driver might just not be an experienced racer. We're not all born at the track, you know.
Even if the owner of the Viper in question isn't here to pipe up, I think it stands better for us to just give the thumbs up over this outcome, say good race.... and of course, better luck next time against a Viper with mods and a driver.
Coincidentally, I'm "all over the place" with my car interests and have taken part in building a 9 second daily-driven Pontiac Grand Prix GTP (former body style, not current) and am currently offering tech advice to a friend across town who is dumping a BUILT LS6 (C5 Z06 V8) into an RX-7..... another car that ought to prove a daily-driven 9 second ride, though it's best abilities will be from a roll.