Kyle Larson turned a shaky points lead into a runaway on Sunday, charging from 10th place in the final laps to beat his own Hendrick Motorsports teammate William Byron by a scant 0.041 seconds in a photo finish at the YellaWood 500, his first career Cup Series victory at Talladega Superspeedway.

The win, confirmed in the official results from Yahoo Sports, came in chaotic fashion. A late red flag flew after Joey Logano flipped in the tri-oval and Riley Herbst hammered both walls, and on the final lap leader Austin Hill ran dry on fuel exiting Turn 4, opening a lane for Larson to shoot through the field, according to a lap-by-lap recap from Racing News. Ricky Stenhouse Jr., Ross Chastain and Cole Custer rounded out the top five, while Denny Hamlin crossed eighth and title rivals Chase Elliott and Ryan Blaney were caught up in trouble and finished 36th and 38th.

A lead that nearly evaporated

The victory erased what had become a nervy week for Larson's championship bid. He arrived at Talladega clinging to just a 5-point edge over Christopher Bell after a flat right-front tire wrecked his car and buried him in 34th at Phoenix Raceway on Oct. 18, an Associated Press report noted at the time.

"I didn't expect to be good at Phoenix, and I didn't expect to be that bad," Larson said that week, adding that his team would try to put the finish behind them and focus on a superspeedway where they've historically run well.

They did more than that. The Talladega win ballooned Larson's championship lead back out to 73 points with two races remaining, putting him in control of the Round of 8 heading into the semifinal cutoff at Martinsville Speedway on Nov. 1 and the championship finale at Homestead-Miami Speedway on Nov. 8. Bell and Hamlin now trail by 74 and 73 points, respectively, with Chase Briscoe — a winner of two straight races at Las Vegas and Charlotte before Talladega — further back, according to Sportsnaut's breakdown of the title scenarios.

A win anywhere in the Round of 8 locks a driver into NASCAR's four-driver championship finale regardless of points, so Sunday's result effectively punches Larson's ticket to Homestead-Miami before a single lap is run at Martinsville — barring a penalty or disqualification. It is a sharp reversal from a week earlier, when a single blown tire had the sport's reigning points leader suddenly fighting for his playoff life.

Byron's runner-up finish keeps his own hopes flickering, but for Hendrick Motorsports it was a 1-2 finish that doubled as validation for a team that has dominated speedways not generally considered its strength. Attention now turns to Martinsville, where Bell, Hamlin and Briscoe will need a big result just to keep pace — let alone catch a Larson team that just turned its most vulnerable week of the playoffs into its most commanding one.