Larson wins playoff opener at Darlington for first career win at track

Larson took the checkered flag at the Southern 500, securing his spot in the next playoff round.
Denny Hamlin led the most laps but had to pit due to loose wheel, allowing Larson to take lead.
Kevin Harvick challenged Larson but was penalized for entering closed pits.
Larson's win marked the 299th for Hendrick Motorsports and 500th for Hendrick engine program.
Victory ended 17-race winless streak for Larson ahead of playoffs.