DAYTONA BEACH, Fla. -- After driving his car as high as third, an ailing Tony Stewart radioed his team he couldn't continue.

``Are you sure? Are you sure?'' crew chief Greg Zipadelli repeatedly asked.

Stewart was certain, climbing from his seat midway through Saturday night's race at Daytona International Speedway while relinquishing the wheel to backup driver J.J. Yeley. His decision ensured another winless race for Stewart, whose streak stretched to 32.

At about the same time, teammate Kyle Busch was making yet another charge to the front as he rolled to his Sprint Cup Series-best sixth victory of the season. It was a stark contrast for Joe Gibbs Racing, which had hoped to have all three of its drivers challenging for the win.

Instead, Busch continued his incredible season-long run in the No. 18 Toyota, his good fortune once again overshadowed Stewart and Denny Hamlin. Yeley drove Stewart's No. 20 car to a 20th-place finish. Hamlin, who was strong late, was spun and wound up 26th in his No. 11 Camry.

``The past couple of years, the 18 car has not been so great with luck, and the 11 and 20 seemed to have it,'' Busch said. ``Tony had a good car, and sorry that he had to get out for feeling ill. And Denny had a pretty good car and pretty fast car, too, and he got back in traffic and got mixed up in some of those melees.

``We were able to stay clear.''

It's been the story of the season for Busch, who is starting over with a new team this year after a turbulent run at Hendrick Motorsports. Fired by that team so it could sign Dale Earnhardt Jr., JGR snapped up Busch in an effort to even out its three-car team.

But Busch has dominated his teammates, and Saturday night's win was his 12th of the year spanning NASCAR's top three series.

His six Cup wins have earned him 60 bonus points for seeding purposes when the Chase for the championship begins. The next closest competitor is Carl Edwards, who has earned 20 bonus points and lost an opportunity to close the gap when Busch beat him in a drag race Saturday night that ended under caution.

``That's what hurt the most,'' Edwards said of Busch grabbing another 10 bonus points. ``He's really setting himself up for a great start to the Chase. You know, if he wins one or two more, he's almost got a freebie there if he blows an engine or has a bad race or something.