Two-time Cup champion Tony Stewart also put a lot of effort into the race, leading 132 of the 284 laps. But he was left to ponder what might have been after his winless string was extended to 31 races by more of the hard luck that has dogged him all season.
It was the first victory for Busch since the Penske Racing driver won in September at California Speedway. And there hasn't been much to celebrate since.
Other than coming in second to teammate Ryan Newman in the season-opening Daytona 500, the 2004 Cup champion had finished in the top 10 only once in 2008 and came into this event 22nd in the points. But Sunday turned out to be his day, thanks to crew chief Pat Tryson's decision to keep his No. 2 Dodge on track when Stewart and several other lead cars pitted during a late caution period.
When rain eventually ended the race 17 laps short, with the field under a red flag on pit road, Busch had his 18th career victory and Stewart was an unhappy 13th.
"I've been on the flipside of it plenty of times," Busch said.
"There's those times when you just grit your teeth and go, 'What could we have done different? Why did it happen this way?' So it isn't pretty, but we'll take it.
"That's the beauty of Sprint Cup racing is the competition level is always at its best. Sometimes the guys that have fast race cars don't win because they got outdueled in the pits with pit strategy. You take 'em when you can get 'em because you get burned plenty of times the other way."
Runner-up Michael Waltrip, who had not finished better than 23rd this season, used the same strategy as Busch. The two-time Daytona 500 winner said he was hoping the race would go to the end because he believed he had a faster car than Busch. But Busch believed he could hold the top spot.
'I felt like it was going to be a great duel down to the end with everybody on old tires, everybody would have been slipping and sliding," Busch said. "I felt we had track position and I felt like my fire and desire was going to overcome anything today to get into Victory Lane.
"Once I saw that we were leading and we were out in front with 26 (laps) to go, that good old Kurt Busch jumped up on the wheel and I told myself, 'Don't let your team down. This is what you live for. This is what you race for, and that is to get into Victory Lane."
Stewart, who dominated the second half of the race on the 1.058-mile oval, held off a challenge from two-time reigning Cup champion Jimmie Johnson late in the race and appeared on the way to his first victory since August at Watkins Glen, N.Y. But Stewart and most of the other drivers who had been racing at the front of the pack did not have enough gas to get to the end.
On lap 271, Dale Earnhardt Jr., who had been in the top 10 all day, started toward pit road and was hit from behind by Jamie McMurray, who then spun into David Ragan, bringing out a caution.
Stewart and the rest of the front-runners pitted under the ensuing yellow flag, while Busch and seven other drivers who had pitted more recently than the leaders, stayed on track.
The race restarted on lap 279, but there was another caution on lap 280, with Clint Bowyer and rookie Sam Hornish Jr. crashing, then Juan Pablo Montoya slamming into series points leader Kyle Busch, Kurt's younger brother, moments later. Montoya was later assessed a two-lap penalty by NASCAR for rough driving and finished 32nd.
The rain that had been threatening for much of the afternoon began falling during that caution and, moments after the cars were red-flagged onto pit lane just before completing lap 285, NASCAR called the race, leaving Busch on top, ahead of Waltrip, J.J.
Yeley, Martin Truex Jr., Elliott Sadler, Reed Sorenson and Casey Mears, all of whom had stayed on track during the previous caution.
Within minutes after the race was official, the sky opened up and lightning began flashing around the speedway, emptying the stands in a hurry and forcing Busch to hold his victory celebration in the shelter of the garage area.
Stewart took awhile getting out of his car and could hardly believe his fate.
"It's just been the oddest year I've ever seen for this race team," he said. "It's just frustrating. There isn't anybody that's going to tell you any different than that. There's nothing you can do. If there was something we could do about it we'd change it.
"It's not because of lack of effort," added Stewart, who took two tires on his final pit stop and finished 13th. "I've got some of the best guys in the garage area and I've had 'em for 10 years.
It's the worst string of bad luck we've ever seen, but there's nothing we can do about it."
Kyle Busch wound up 25th on Sunday, while series runner-up Jeff Burton, who finished 12th, climbed from 103 points behind to just 64 heading into Saturday night's race at Daytona.
(Copyright 2008 by The Associated Press. All Rights Reserved.) AP-NY-06-30-08 0349EDT
