Kyle Busch finally figured out Martinsville Speedway in his truck victory on Saturday.

He dominated it on Sunday in the STP 500. Busch led for 352 laps and pulled away on a restart with 11 to go, outrunning A.J. Allmendinger to the finish for his first NASCAR Sprint Cup victory on the series’ smallest, oldest oval, and a sweep of the two-race weekend.

Busch, who won for the first time in 31 starts at Martinsville in the truck race Saturday, earned his 35th Cup victory on the season’s first short track. The race was run in bright sunshine, but the cool temperatures never let the track get quite as sticky as it normally does.

The finish looked nothing like the leaderboard for most of the race, but Busch and teammate Matt Kenseth stayed out when a caution flew with 15 laps to go while the rest of the contenders pitted for fresher tires.

The option to pick the inside or outside line as the leader on the restart was great for Busch, but not for teammate Kenseth.

‘‘That was the key to the race, being able to restart on the bottom like that,’’ Busch said after choosing the inside line, putting Kenseth outside.

‘‘We all talked as a group earlier this morning about how we were going to do that and what we were going to do, and we all said, with 10 to go, it’s pretty much off limits. It was 11 to go, so it was pretty much right on the brink there, so, ‘Sorry Matt.’?’’

When the green flag flew, Busch sailed off, Allmendinger beat Kenseth to the inside position, and Kenseth got shuffled back to 15th.

Busch, meanwhile, led the most laps at Martinsville since Bobby Hamilton was out front for 378 in April 1998.

Allmendinger was second, followed by Kyle Larson, Austin Dillon, and Brad Keselowski.

‘‘I was kind of hoping we'd stay green the last 120 laps,’’ Allmendinger said. ‘‘I figured that wasn’t going to happen, but I was praying we had a shot at that because I felt like if that happened, we had a great chance to win the race.’’

Several other drivers who pitted before the final restart started in the sixth row, or further back, of side-by-side racing, and while Larson and Keselowski recovered for top-five finishes, others got caught up in traffic, allowing Dillon to vie with the leaders.

It was the second time Martinsville turned out to be a huge disappointment for Kenseth.

Last spring he wrecked race leader Joey Logano with 46 laps to go, earning himself a two-race suspension. This time he seemed poised to challenge Busch for the lead with 35 laps to go until Jamie McMurray blew a tire and caused a caution, bunching up the field.

‘‘I was a little worried there toward the end before that last caution came out that Matt was catching me,’’ Busch said. ‘‘He was on me pretty good, and I wasn’t sure that I had enough brake in order to handle the rest of the day, but fortunately we got a yellow there.’’

The race also was a lost day for Denny Hamlin, one of the favorites going in and the defending champion.

He was running fifth at 221 laps after overcoming a pit road penalty. But he lost control of his car heading into Turn 1 and slammed into the wall, sending him to the garage. He finished 42d.