William Byron, driver of the #24 RaptorTough.com Chevrolet, takes the checkered flag to win the Cup Series Blue-Emu Maximum Pain Relief 400 at Martinsville Speedway Saturday night. (Meg Oliphant/Getty Images)
The first night race for the Cup Series at Martinsville Speedway was a cakewalk for Hendrick Motorsports — until a late caution sent the race to overtime, that is.
But William Byron survived a final restart and a mistake on the white-flag lap to win Saturday night’s Blue-Emu Maximum Pain Relief 400 at the 0.526-mile short track.
Byron led 212 of the 403 laps. Teammate and pole winner Chase Elliott l…
