Californian Cole Custer was the only former Auto Club Speedway winner in the field for Saturday's Production Alliance 300 NASCAR Xfinity Series race in Fontana, California.

Three overtimes, 12 cautions and more than three hours of official race time later, Custer was still the only former winner in the Fontana field, having beaten runner-up Noah Gragson to the finish line by .565 seconds.

It was a long day's journey into night, a race that started in mid-afternoon and unexpectedly ended under the lights in temperatures that dropped appreciably between the start and the finish. The three overtimes extended the event 15 laps beyond its scheduled distance of 150 circuits at the 2-mile track.

But Custer was the clear class of the field, leading 80 of the 165 laps and twice charging like a rocket from the outside of the fourth row to the lead after slower-than-usual late pit stops.

He got his second victory at Fontana in a No. 07 Ford that was a partnership entry between Stewart-Haas Racing and Bobby Dotter-owned SS Green Light Racing.

Custer was moonlighting - literally, as it turned out - from his Sunday ride in the No. 41 SHR Ford Mustang, which he'll be racing in the WISE Power 400 (3:30 p.m. ET on FOX, MRN and SiriusXM NASCAR Radio).

"Man, it was just an awesome car," Custer said during his post-race frontstretch interview. "That thing was just a rocket ship all day. I can't thank Bobby Dotter enough - everybody that was involved on this car.

"It was unbelievable how fast we were. It's awesome to win at home - can't wait for tomorrow."

Gragson was competitive all day, leading 25 laps. Despite sliding though his pit stall during a pit stop under the eighth caution on Lap 125, he surged back to the front from 14th, retaking the top spot on the second lap after a restart on Lap 129.

Five laps later, however, Custer regained the lead and held it for all but one of the last 31 laps, through four more cautions and three overtime restarts.

"I felt like the car was really close all day, just struggled with the cloud cover and the temperature change - too loose or too tight," Gragson said. "Hats off to all the guys on the 07 car and Cole Custer. He was really fast today."

Trevor Bayne, the 2011 Daytona 500 winner, ran third in his first Xfinity Series start since a one-off in 2016. Josh Berry was fourth, as JR Motorsports drivers claimed four of the top eight finishing positions, with Gragson second, Sam Mayer sixth and Justin Allgaier eighth.

Anthony Alfredo parlayed tire strategy into a fifth-place finish. Pole winner AJ Allmendinger recovered from an unscheduled pit stop for a loose wheel to come home seventh. Riley Herbst and Ryan Sieg were ninth and 10th, respectively.