BRISTOL, Tenn. (AP) — Austin Dillon figured fourth place was about all he could get Friday night until the old Brad Keselowski-Kyle Busch rivalry reared up at Bristol Motor Speedway.

Keselowski hit the back of Busch's car as the defending Sprint Cup champ tried to clear him from the lead, cutting down a tire and sending Busch into the wall four laps from the scheduled end. Then just as suddenly Keselowski ran out of gas during the caution — leaving a happily surprised Dillon out front to win the Xfinity race in overtime Friday night.

"I was actually just enjoying what was going on (up front) trying to get there," Dillon said about the chaos.

For the last 50 laps, the race looked like a classic faceoff between Busch and Keselowski who no one would consider friends.

While Keselowski's tactic to many diehards was just a traditional Bristol bump-and-run, it's sure to stir up a Busch-Keselowski tussle that's frequently goes from zero-to-60 in seconds.

Keselowski described Busch as another name for a donkey during driver intros at Bristol in 2010. Keselowski detailed their rocky relationship on and off track in a blog last year.

The two get a chance to tangle once more here Saturday night in the Sprint Cup event.

"We were battling really hard and definitely didn't want to see it end that way," Keselowski said.

"He's a dirty racer," Busch responded when asked by ESPN.

Dillon didn't care about the circumstances only that he was broke cleanly in the green-white-checkered finish to beat Justin Algaier in second and Kyle Larson in third.

"Even when they were pushing us, we had to remain calm," said Dillon's crew chief, Justin Alexander. "Things unfold and you're sitting there pretty much where you need to be."

Larson had led for 200 of 308 laps, but was overtaken the Keselowski and Busch.

Dillon's younger brother, Ty Dillon, made it a three-car race as he mixed it up between the two Sprint Cup champs. In fact, it was Ty Dillon, who emerged on top when that trio raced three-wide on Bristol's slippery, tight track. But Dillon couldn't sustain his edge and his chances ended for good when he hit the back of Busch's slowed machine.

Dillon thought the Keselowski-Busch dustup might increase the walk-up sales for Saturday night's next round. "We should sell some tickets tomorrow night," he said.

All the fussin' and fuedin' up front was just fine with Dillon, who won his eighth career Xfinity victory and first at Bristol.

"It was just a war of attrition and we had a pretty good car," Dillon said. "Maybe not the fastest car, but the car that won."

WHO'S HOT: Justin Algaier figured on finishing seventh until the late chaos lifted him to second. It was his fifth top-10 finish in his past six Xfinity races at Bristol.

WHO'S NOT: Daniel Suarez, who had a strong run at Bristol Motor Speedway ruined for the second time in three days. Suarez led 77 laps in the truck series here Wednesday night when a late crash doomed him to 29th. He led Xfinity practice Thursday and was bidding for a top-10 finish when another accident knocked him back.

THEY SAID IT: "I've never seen the fans get that involved in something like that that really wasn't a major deal, nobody wrecked each other in a caution or something like that. But fans were definitely getting excited," runner-up Justin Algaier said of the Busch-Keselowski tangle.

THE BIG ONE: Teammates Erik Jones and Daniel Suarez clipped each other on lap 245, causing significant damage to the two Joe Gibbs Racing entrants. Jones, the pole sitter, was running ninth at the time. The crash collected four other cars. Jones had won the Xfinity race here this past April.

UP NEXT: Road America, Elkhart Lake, Wisconsin, Aug. 27. Paul Menard is the defending race winner.