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.

"They are doing it right, and that's going to be hard for the rest of us. Those points - we are going to have to make them up. That's just the way it is.''

The advantage is also growing over his teammates. Hamlin has one win this season, 10 bonus points and is currently seventh in the standings. The winless Stewart, a two-time series champion, has slipped to 12th in the points with just eight races remaining to solidify his spot in the Chase.

He was expected to contend at Daytona, where he won this race in 2005 and 2006 with dominating performances. Instead, he fell ill overnight and spent most of Saturday in the care center receiving intravenous fluids to prepare him to at least start the race.

"Before the race, the nurse said she was going to buy us a couple of hours and we got three hours out of it. We still had to go out there and try,'' Stewart said. "I felt nauseated and I was dehydrated. They ended up putting five IV fluids in me, just to get me comfortable. I knew I wasn't feeling any better and it was getting worse as we were going.''

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Still Stewart, who started 17th, wasted little time driving through the field and had gotten his car as high as third. He didn't flinch during the first two pit stops, but decided to get out during the third.

"I thought we were going to be able to (make it) for the first two runs, but once the car got a little bit loose and we had to start really sawing on the wheel, it's like it zapped the energy out of me and I started making mistakes,'' Stewart said. "I wasn't doing us any favors by not being 100 percent. It wasn't worth putting those guys at risk and me making a mistake in front of them and creating a bad day for those guys.

"I was trying to be responsible and respectful to my race team and to the rest of the competitors out there."