After 15 years of the Professional Bull Riders (PBR) Built Ford Tough World Finals in Las Vegas, no rider has been able to pull off repeat world championships. It's hard.

Owen Washburn came the closest, finishing fourth the year after his 1996 world championship. Since then, talented riders like Michael Gaffney, Troy Dunn, Chris Shivers, and Mike Lee have all succumbed to the fierce competition and even fiercer bulls.

"Everyone who's won has been capable of repeating," says PBR livestock director Cody Lambert. "The main factor is injuries. They're part of the sport, and it's tough to keep from getting banged up."

The drought could change this year when defending champion Guilherme Marchi nods his head Oct. 30 for the first of his eight rides in front of a packed house at the Thomas & Mack Center in Las Vegas. The Brazilian finally broke through last year and shed his "bridesmaid" image-he finished second in 2006- 2008-en route to a record $1.5 million season. He's enjoyed a solid 2009 season on the Built Tough Fort Series to put himself in contention to make PBR history.

While some will cheer for Marchi, others will root for standings leader Kody Lohstroh or rising star J.B. Mauney. Either could get hot and walk away with the title and the $1 million bonus.

Marchi left little room for drama last year with a dominating lead heading into the event. Not so this year in what could be PBR's tightest margin of victory.

"It's hard to decide who to bet on," says Ty Murray, the PBR president and two-time (non-consecutive) world champion. "I've seen Kody and J.B. get hot at the finals, and I've seen Guilherme close out a championship. These guys are all at the highest level of their game right now."

Last year, Marchi won it all but shared the spotlight with retiring champions Justin McBride and Adriano Moraes, whose appearances at the PBR Finals served as their personal farewell tours.

Whoever wins this year will have earned it, posting rides on the best bulls in the business. Lambert singles out Bones, the reigning PBR Bull of the Year, along with Chicken on a Chain, Voodoo Child, Big Tex, and Code Blue as the big-time bulls to watch.

With all the talk of a three-man race, let's not forget other possible winners. There's Shivers, the twotime PBR champion, whose next crown would match Moraes as the only men with three titles, plus veterans Wiley Petersen, Ross Coleman, Zack Brown, and Sean Willingham, along with rising stars Brian Canter, Ryan McConnel, and Ryan Dirteater.

When forced to pick his favorite, Lambert gives the nod to Marchi. "If Guilherme is able to repeat, which I think he's very likely to do, it would be great because he'd be able to do something none of the greats have been able to accomplish."