William Byron had the field covered at Watkins Glen International, delivering such a dominant performance that no other NASCAR driver even got to his bumper in the final third of the race.

It was usual for the Cup Series and even more rare for Byron at a road course. The 25-year-old Byron won on a serpentine track for the first time in six Cup seasons, this one being his series-leading fifth victory of the season and making him a favorite to win it all.

"We've worked years and years for this," Byron said, crediting veteran open-wheel racer Max Papis with helping him. "It’s a great win. I don’t know what it means and all that. I don’t read into that. But I think it shows that when we’re at our best, we can perform like this."

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Driving the No. 24 Chevrolet for powerhouse Hendrick Motorsports, Byron overtook Michael McDowell in the first quarter of the 90-lap event and pretty much remained in control the rest of the way. He led 66 laps in all, including the final 33.

Pole-sitter Denny Hamlin was second, nearly 3 seconds back, in the penultimate race of NASCAR's regular season. Christopher Bell was third, followed by AJ Allmendinger and Ty Gibbs.

Martin Truex Jr. finished sixth but failed to lock up the regular-season title for Joe Gibbs Racing. He and Hamlin will vie for the regular-season crown next weekend at Daytona International Speedway.

"It's doable," said Hamlin, who trails Truex by 39 points. "You’ve got to have things go your way, but yeah. If we can talk NASCAR into those 25 points they took away earlier in the season, we’d really make it interesting."

Always-unpredictable Daytona will be the last chance for more than two dozen drivers — most notably 2020 series champion and fan favorite Chase Elliott — to make the 16-car playoffs.

NASCAR VETERAN KEN SCHRADER, 68, WINS RACE IN CANADA

Elliott, a two-time winner at the Glen, had hoped to lock up a postseason spot Sunday. But the Hendrick star qualified in the middle of the pack and then ruined his chances when he ran out of fuel with 36 laps to go. He lost a lap and all hope of winning.

Elliott will have to win at Daytona to make the playoffs for the eighth consecutive season. Bubba Wallace and Daniel Suarez will be equally anxious at Daytona. They are in a tight race along with Gibbs for the 16th and final spot.

"Still stressful at hell, but that takes a little bit of the edge off for sure," Wallace said.

Former series champions Kevin Harvick and Brad Keselowski eased their nerves by locking up playoff spots at the Glen, both securing berths because Byron was a repeat winner.

"It's great to have that off our shoulders," Keselowski said. "We're going to race really hard with nothing to lose (at Daytona); that makes us really dangerous."

MCDOWELL’S MISCUES

McDowell, who notched his second Cup win last week at the Indianapolis Grand Prix, endured several struggles on pit road that cost him a chance at winning back-to-back races. He finished 36th, last.

McDowell, who led 17 laps and won the opening stage, was penalized early in the second for driving through too many stalls while entering his pit. The pass-through penalty dropped him from second to 17th. He had another pit-road penalty in the final stage, that one for crew members going over the safety wall too early.

McDowell ended up back in the pits with 15 laps to go with an engine issue.

"The highs and lows of motorsports," McDowell said. "I think we had one of the fastest cars here today."

UP NEXT

The series goes to Daytona for the regular-season finale on Saturday night. Austin Dillon is the defending race winner.