A.J. Allmendinger won a NASCAR oval race for the first time in his long career.

Taking advantage of mistakes by the three leaders, the 38-year-old Californian cruised to victory by nearly 2 seconds over pole-sitter Noah Gragson in the Xfinity Series race at Atlanta Motor Speedway on Saturday.

"Oh my god,” Allmendinger said as he climbed from his No. 16 Chevrolet. “I won on an oval.”

Indeed, he did.

Allmendinger, who first came to prominence in open-wheel racing, claimed a single victory during more than a decade in the top-level Cup series, and he had three previous Xfinity wins — all on road courses.

Now, he filled in a big hole on his resume.

“All I ever wanted to do was win on an oval,” said Allmendinger, who has only a part-time ride in the Xfinity Series after losing his Cup ride after the 2018 season. “I have a lot of success in so many forms of racing.”

Allmendinger started 30th but quickly showed the strength of his car, spending much of the day running in the top 10.

Then, after the final caution of the day, the top three cars — Chase Briscoe, Austin Cindric and Justin Allgaier — were all caught speeding on pit road.

That pushed Allmendinger into the top spot on the restart with 34 laps to go.

He held on the rest of the way.

Cindric had the strongest car early on, winning the first two stages. But his mistake heading into the pits knocked him back to a 16th-place finish.

Allgaier savaged a sixth-place showing, while Briscoe settled for ninth.

Gragson crossed the line second but picked up a $100,000 bonus from the title sponsor.

He was closing the gap on Allmendinger in the closing laps, but got hoodwinked by the more experienced driver.

Allmendinger gave the impression that his tires were fading, duping Gragson into making a furious run for the front.

Turns out, Allmendinger's tires had more grip than he was letting on. Gragson didn't have anything left at the end.

“I got beat by his experience,” the 21-year-old Gragson conceded. “He had the bait waiting there. I took it, and he reeled me in.”

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