DARLINGTON, S.C. The Southern 500 was held at Darlington Raceway on Labor Day weekend from the track's opening in 1950 as NASCAR's first superspeedway through 2003.

Then, after seeing its traditional date shuffled to tracks near Los Angeles and Atlanta, the "Track Too Tough to Tame" was reassigned the holiday weekend date.

And, boy, did it deliver a thriller, with a great late-race duel setting the stage for a shootout finish. Carl Edwards won the race off pit road following a late caution, then outdueled polesitter Brad Keselowski and Denny Hamlin to capture the 367-lap event.

It was Edwards' 25th victory in Sprint Cup competition, and his first at Darlington. Keselowski, who led the most laps, squeezed past Hamlin in the final corner to salvage second, with Hamlin, Joey Logano and Kevin Harvick rounding out the top five. Keselowski dominated most of the night, leading nearly half of the race's first 300 laps.

Caution after caution kept the field close in terms of cars on the lead lap. It also pushed race strategy to the forefront because of Darlington's rapid tire-wear rate.

Steve Letarte, a Sprint Cup crew chief until joining NBC as an analyst this year, said, "This track is very asymmetrical and turns one, two, three and four are all completely different. It's a very tough race track on new tires and old tires."

And drivers.

Chase Elliott and Danica Patrick were among those eliminated by run-ins with Darlington's walls, and numerous others soldiered on with huge swatches of tape patching damage. Even more bore the familiar "Darlington stripe" on the right-hand side of their cars from brushes with the SAFER barrier, usually the result of worn tires that quickly lost the prime of their precious traction.

Late in the going, with the teams' allotment of fresh tires in short supply, some drivers began altering their driving styles to save as much wear and tire on rubber as possible. On lap 307, third-running Kurt Busch spun in the third turn after being punched in the rear by Martin Truex Jr. That made for the 17th caution of the night, which tied the track record.

"I had no idea he was going to slow down that fast," Truex told his crew. "I just ran him over."

The plague of cautions kept a large percentage of cars on the lead lap, but with each restart, the cream of the crop was virtually the same: Keselowski, Busch, Truex, Joey Logano and Kevin Harvick.

With 22 laps to go and tires about maxxed out, Keselowski, Harvick and Edwards were all nose to tail. Harvick briefly lost the second spot to Edwards, then managed to regain it on the next trip around the 1.366-mile speedway.

Keselowski, meanwhile, was high-tailing it through lapped traffic, weaving through the pack and trying to shake his pursuers. He briefly pulled away to a two-second lead over Harvick, then saw it halved by the 2014 race winner.

Then, with 12 laps remaining, Jeb Burton spun through the first and second turns for a race-record 18th caution. That gave the entire field a final chance to pit for fresh tires, and Edwards won the race off of pit road -- and, just eight laps later, the race.