Watch: NASCAR Xfinity Race at Texas decided by two one-thousandths of a second

Mayer entered the 2024 season as a title favorite, but one year after a breakout season in 2023, he'd struggled in the early portion of the season, entering Saturday's race just 16th in the playoff standings, 19 points below the playoff cutline. However, a win would automatically qualify either driver into the playoffs, and ensure them a chance to chase the championship in the fall. 

With one driver looking to possibly save his season and the other looking for his first NASCAR win, something had to give. Coming out of turn four on the final lap, both drivers slammed into each other on the front stretch, trying to gain every possible inch over their competitor.

What followed was, as they say, a moment in history.

Sieg went from experiencing the joy of victory to experiencing the agony of defeat in just a few hundred feet, while Mayer likely saved his championship hopes with a win that gets JR Motorsports its first checkered flag of the 2024 season. 

Via the Dash 4 Cash program, Mayer also won an extra $100,000 with his win on Saturday, finishing ahead of fellow Dash 4 Cash competitors in Justin Allgaier, (third) Chandler Smith (15th) and Sheldon Creed (19th). 

"The amount of adversity we've had to fight this entire year so far, to come to a mile and a half that I want to say I'm good at, it took every ounce of me to do that today," Mayer said. "My spotter (Kevin Hamlin) may have won that race because he told me the bottom of three and four was better, so props to him."

Mayer will be entered in the Dash 4 Cash program again next week at Talladega, and if he can finish above his fellow competitors again, will win another $100,000 bonus.

While Mayer and the No. 1 team celebrated, Sieg and the No. 39 team stood on pit road, contemplating what they could've done differently in the closing laps. 

"It sucks. We had a really good car, just got tight at the end. I tried to change my line and do different things," Sieg said, documenting the final run of the race. "I saw (Mayer) coming and at the end I was just trying to run him in the wall and win the race, we're so close, you know. It just sucks. I've been in second too many times."

While Sieg was able to drive away from the field on the last restart, including the dominant car on the day in Allgaier, Mayer had just enough in his Camaro to run him back down and take home a win that will be playing on the highlight reels for the end of time. The finish is officially the second-closest margin of victory in NASCAR Xfinity Series history. 

There's a strong likelihood of another photo finish for the Xfinity Series next weekend as well, as the series heads to the high banks of Talladega Superspeedway. The green flag for next week's race is set to fly at 4 p.m. ET and will air on Fox, MRN and SiriusXM NASCAR Radio.