Martin Truex Jr. wins opening two stages Sunday to clinch regular-season championship

— -- 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.

No matter where Truex finishes the race, he will leave Darlington with at least a 61-point lead in the standings, meaning he can't be knocked off the top spot in the regular-season finale Saturday at Richmond Raceway.

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 Kyle Busch.