Keselowski led 446 of the 500 laps around the shortest track on the NASCAR schedule, but was challenged a handful of times by Chase Elliott — the only driver to pass Keselowski on the track Sunday.
Although Elliott led 49 laps, a late caution sent the field to pit road and Keselowski beat Elliott back to the track. Elliott could never get close enough to challenge Keselowski for the win again.
“The car was really good. Just a great day for a team,” Keselowski said. “Just one of those days you dream of as a race car driver.”
The win was the third this season for the new Ford Mustang. Toyota has won the other three races.
Keselowski started third behind teammate Joey Logano, who led the first five laps of the race. Keselowski briefly nudged Logano out of the groove on the sixth lap and took off for the rout that earned him his second Martinsville grandfather clock.
Elliott finished second in a Chevrolet from Hendrick Motorsports, while Kyle Busch was third in a Toyota for Joe Gibbs Racing. Busch had won two consecutive Cup races before Sunday, the Truck Series race Saturday at Martinsville, and was seeking a weekend sweep.
Busch notched his fifth top-five finish of the season while making his 1,000th career NASCAR national series start.
Penske driver Ryan Blaney was fourth, while Gibbs driver and five-time Martinsville winner Denny Hamlin was fifth.
Ford drivers took six spots in the top 10, while Gibbs and Toyota claimed three of the slots.