Dover, Del. — Denny Hamlin went back-to-back at Dover Motor Speedway, holding a late lead through a rain delay and an overtime finish Sunday for the Joe Gibbs Racing driver's series-best fourth victory of the season.

With a 20th-place finish, Dillon -- the No. 32 and final seed in the In-Season Challenge -- advanced to the final round of the tournament, where he will race Gibbs (who won his matchup against Tyler Reddick) for a $1 million prize in next weekend's Brickyard 400 at Indianapolis.

Hamlin survived a late charge from his teammate Chase Briscoe on fresher tires to take his fourth Cup Series victory of the season and the 58th of his career, which leaves him sitting alone in 11th on the Cup Series' all-time wins list.