DARLINGTON, S.C. — Martin Truex Jr. clinched the Monster Energy NASCAR Cup Series regular-season championship by winning the opening two stages Sunday night in the Southern 500 at Darlington Raceway.

Truex nearly made it a sweep of the night, but suffered a flat tire when trying to hold off Denny Hamlin for the win with two laps remaining. He finished eighth in the race, but his 107-point advantage over Kyle Busch in the standings was well more than enough of the 61-point cushion the Furniture Row Racing driver needed entering the regular-season finale next Saturday at Richmond Raceway.

“I was driving my guts out at the end trying to hang on,” Truex said. “It’s unfortunate we blew the tire, but I’m really proud of everybody on this team for an amazing season so far.

“To lock up the regular-season points is a huge accomplishment for us, for our team. We’ve come a long way in just a few years together. I wish we could have won, but that’s the breaks.”

As part of the revised NASCAR points system implemented this year, NASCAR added extra incentive for drivers to pursue the regular-season title.

NASCAR is awarding “playoff points” this season — points that are added to a driver’s total following the reset in points for the first three rounds of the playoffs.

Drivers earn five points for a race win and one point for a stage win during a race. The top 10 in the regular-season standings also earn playoff points on a 15-10-8-7-6-5-4-3-2-1 scale.

Truex has the most playoff points of any driver. Not including points for where drivers finish in the regular-season standings, Truex has 37 playoff points — 17 more than second-place Busch, who finished second in Sunday’s race.

“I don’t know if it means more to the team – it’s not harder to do because of [the playoff points],” Truex said. “It’s a lot to be proud of. … We can go to Richmond without any pressure, which is awesome.”

Truex likely will have more than 20 points on the entire field entering the 16-driver playoffs, meaning that he could likely survive at least one bad race in each of the playoff rounds and still advance. Last year, a blown engine at Talladega kept him from advancing to the semifinal round.

“It was a good decision to make that change,” Truex said. “They did it because of the difficult level [of winning the regular-season title] and guys that had performed at a really high level in the regular season and had a bad race or two in the playoffs and lost their shot at winning the championship.

“It would suck to win the regular-season championship and just completely lose your shot at winning the title based on some kind of racing luck.”