DOVER, Del. -- Kurt Busch left a rocky start to the Chase and his fiercest rival behind him.

Busch stormed into contention for a second Cup championship, holding off fellow Chase drivers Jimmie Johnson and Carl Edwards to win Sunday at Dover International Speedway, tightening the leaderboard in a playoff where no driver has emerged as a clear-cut favorite.

Busch, though, is in the mix.

His No. 22 Dodge seemed only to get stronger over the 400-mile race and he beat Johnson, his long-time antagonist, on the final restart to take the checkered flag for the second time this season. The win pushed Busch from ninth to fourth in the points standings, only nine points out of first.

Only 15 points separate the top eight drivers with seven races left.

Edwards and Kevin Harvick share the points lead in the Chase for the Sprint Cup championship standings entering round 4 of the Chase at Kansas Speedway. Harvick is seeded first because of a tiebreaker.

Busch, the 2004 champion, won his 24th career race and for the first time at Dover.

"To win a Sprint Cup race in the Chase, this is what it's all about," Busch said.

Johnson leads active drivers with six career victories at Dover and traditionally dominated Chase races. Sure enough, after a tough start to the Chase, the defending five-time champion led the majority of laps and proved the No. 48 is far from finished.

Kurt Busch celebrates in Victory Lane after winning the Sprint Cup race at Dover International Speedway. Busch moved up to third in the point standings with the win. Geoff Burke/Getty Images

"Are we out of this?" said Johnson, rubbing his chin with a smile.

Not yet. Not by a long shot.

Johnson got beat off the last two restarts, spinning his tires on the first one and he mistimed when Busch would accelerate on the second.

"I hate leaving points on the table, and we have these first three," Johnson said.

Losing to Busch had to sting.

Busch made his move off the final restart with 43 laps, leaving Johnson and the rest of the field in the mirror.

Johnson's reign was considered by some to be on the ropes after he finished 10th and 18th in the first two Chase races. But his strong result on one of his favorite tracks moved him only 13 points behind the leaders and feeling confident. He has five straight top 10s, including one win, at Kansas.

"Giving up a win by not getting a good restart, I'll think about it tonight," Johnson said. "But big-picture wise, we'll take it."

The winning move against Johnson made the victory more meaningful for Busch. Two of the sport's top drivers have developed a long-simmering rivalry -- trading paint and barbs -- over the years. It reached a boiling part at Richmond when Busch called Johnson a "five-time chump."

"To beat your arch nemesis, that's just icing on the cake. That's pretty sweet," Busch said.

Johnson, who led 157 laps, was second and Edwards was third. Edwards, who won the Dover Nationwide race on Saturday, dominated most of the race until a pit road speeding penalty cost him a lap. Without that infraction, Edwards just might have won the race and made it a weekend sweep.