Riggs, the 16-year-old son of retired NASCAR Monster Cup Series driver Scott Riggs, passed defending Kingsport track champion Kres VanDyke for the lead on a lap-76 restart and led the remainder of the 125 laps around the 3/8-mile concrete oval.
But with sweltering temperatures and muggy conditions, many of the drivers were suffering from heat issues. Riggs took advantage and his No. 99 Ford pulled away to an eight-car-length win over the No. 15 Chevrolet of VanDyke.
"It's a very finicky line around here, but I think I got it figured out," Riggs said. "I was able to stay up in the banking, take a higher line and that helped save our tires. When I was behind Kres, he kept running the lower line, but I was just trying to keep my tires cool and save where I could pounce on him."
VanDyke started third, but passed Deac McCaskill for second place on the opening lap. He then stalked the No. 99 Ford of Riggs during the opening laps before passing him for the lead on a lap-28 restart.
He held the lead until Riggs made the winning pass after a mandatory caution period.
Riggs set fast time in qualifying with a lap of 14.861 seconds (90.842 miles per hour). However, he explained it wasn't where he was running during the last half of the race.
"I ran a different line in the race than I did in practice," Riggs said. "Kres taught me a lot when I was following him. I saw where he was beating me at and knew I could use it against him later in the race. He was looser than I was, and he could go to the center (of the corner) and stay low and I couldn't stay low. But when I was able to get on the throttle, I knew I would be a lot better than him."
VanDyke, the local favorite, went from his car to the EMS trailer — where he was given fluids to cool down — in the infield after the race. He talked about the conditions after a brief rain shower had halted the action and turned the cars into rolling saunas the second part of the race.
"I don't know how hot it was in the car, but I don't even remember the last few laps," VanDyke said. "It was excruciating hot."
But, he felt the race was lost by his car being slow to come up to speed on the restarts and not being as good when he was running in traffic.
"It has a stumble in the carburetor on the slow-speed restarts and I couldn't get a good start on anybody," VanDyke said. "Other than that, we were good. In clean air, I could run as fast as anybody. But once I got behind somebody, it was harder to maintain my distance."
Lee Pulliam, the defending NASCAR All-American Series national champion who won at Bristol in May, finished third after a 13th-place qualifying run. Sam Mayer and Deac McCaskill rounded out the top five.
"We had a really good race car there," Pulliam said after taking a few minutes to cool down. "We kept hitting the wrong line on the restart, having to pass the same cars over and over. We passed a lot of cars and got the race car on the right track. I feel good about the car, the set-up and what we brought to the table today."
Derrick Lancaster, who won earlier this season in weekly action at Kingsport, placed sixth before requiring attention from EMS workers. Josh Berry, driving a No. 88 Chevrolet owned by Dale Earnhardt Jr., finished ninth, and Ty Gibbs, the grandson of former NFL coach and NASCAR team owner Joe Gibbs, finished 12th.
Among the other local entries, Trey Bayne, the younger brother of NASCAR Cup Series driver Trevor Bayne, was spun out on lap 27. He came back to finish 14th, Nik Williams of Chuckey was 16th, Hayden Woods of Piney Flats was 17th, Wayne Hale came in 19th and former NASCAR Xfinity Series Rookie of the Year Danny O'Quinn from Coeburn, Va., was 21st after motor issues.
Bigfoot, driven by Larry Swim, raced to a sixth consecutive win Saturday night at the Beef O'Brady's Monster Truck Madness event at Bristol Motor Speedway.
He had the fast time in qualifying at 25.01 seconds around an infield course and then beat Quad Chaos, driven by Aaron Cain, in the final round of eliminations.
Stone Crusher, driven by Steve Sims, was the freestyle competition winner, scoring 32 points to edge the Hooked truck of Bryan Wright by one point.