SPARTA, Ky. (AP) — Tyler Reddick crashed the opener of the NASCAR Xfinity Series playoffs on Saturday at Kentucky Speedway by running away with his first career victory.

The 21-year-old led 66 laps, including the final 39, and beat Chip Ganassi Racing teammate Brennan Poole to the finish line by 14.540 seconds. The margin of victory was the largest in the 23 times the series has raced on the 1.5-mile track since 2001.

"It was definitely one of those nights," said Reddick, who is running a partial schedule this season. "The car was great."

Reddick had not led a lap in his previous 14 races in the series this season but passed Ryan Preece for the lead on lap 126 and cycled back to the front with 39 laps remaining after green flag pit stops.

The lead grew from there as the race stayed caution-free to the end.

"I was expecting a caution and it just never came," Reddick said. "Every lap that went by I'd think about it more and more. It's hard not to when the laps are winding down like that and you have a good-sized lead like that. You're just waiting for something to go wrong and it just didn't happen tonight. We had good fortune and we put ourselves in great position."

Poole started eighth in the No. 48 Chevrolet and his career-best second-place finish made him the top driver among the 12 who made the playoffs.

"I felt like we had a really good car all weekend," Poole said. "We made good adjustments throughout the race. One round I was a little bit too loose and lost a bunch of track position on my teammate. I really think that was the difference between us getting to victory lane and him winning. I'm really happy for Ganassi to finish one-two and for Tyler to go to victory lane."

Justin Allgaier entered the race as the No. 2 playoff seed. A flat tire in the early going Saturday put him two laps down, but he rallied to finish third and leads the points with the series set to visit Dover International Speedway next.

"We might not have won the playoffs tonight but I think we definitely salvaged what we needed to tonight to be able to move ourselves forward," Allgaier said.

By finishing fourth, Preece tallied his third top-five finish in three starts with Joe Gibbs Racing. Playoff contender Cole Custer finished fifth. Custer started third and swept the first two stages. He led 49 laps and is second to Allgaier in the points standings.

William Byron, who started the playoffs as the No. 1 seed, made an unscheduled pit stop early in the final stage to address a loose wheel and lost a lap. He rejoined the race in 27th place and finished 18th.

Defending race winner and playoff contender Elliott Sadler finished sixth.

Joe Gibbs Racing swept the front row for the series' July race at Kentucky Speedway and did it again Saturday.

Kyle Benjamin earned his second pole in five starts this season when the 19-year-old posted a lap of 182.229 mph with less than one minute remaining in qualifying. Moments later, Preece completed a 182.186 mph lap to bump playoff contender Custer from a front row starting spot.

Benjamin led 52 laps and finished 12th.