This is it. For those Lucas Oil Off Road Racing Series titles that haven't been sealed, or at least stuffed halfway into the bag, it's one last chance to make something happen, to look for that little racing miracle that will make the difference between champ and chump.

It's not just the final round on Saturday at Firebird Raceway in Chandler, Ariz., but on Sunday follows the Challenge Cup races – Pro 4 vs. Pro 2 and Pro Buggy vs. Pro Lite in races for the big money.

With a single round left, Carl Renezeder is already champ in Pro 4. He's been watching his Pro 2 title hopes slip away in the latter part of the season, even as Brian Deegan, a rookie in the class despite being a seasoned competitor, began his ascendance. It will take a catastrophe for Deegan not to claim the title in his first year as a competitor. Rob MacCachren will likely be settling for second, unless a bad day for him coincides with a great race for Renezeder. Rob Naughton, who won here in March, is trying to take fourth in the standings away from his teammate, Jeremy McGrath.

Deegan is fighting for not one, but two championships. Pro 2 is practically wrapped up, but Pro Lite could go either direction. Deegan holds a tiny three-point lead over Chris Brandt, who led the points for most of the season. It will be one of these two – who traded victories at Firebird in March – as Cameron Steele, Rodrigo Ampudia and Casey Currie are well back of this fight. Whoever wins on Saturday will likely be the champion.

In Pro Buggy, Mike Porter is in a similar situation to Deegan's Pro 2 position – practically, but not officially, the champ, with a 39-point lead over Jerry Whelchel. Whelchel is still in a fight for second in the points with Steve Greinke and Justin Smith, though, who are nine and 10 points behind, respectively.

Curt Geer has a solid, but not insurmountable, lead over Jerry Mason in Limited Buggy. His 18-point margin should be enough, but this is short course and anything can happen. It's considerably closer in Super Lite, where Chad George is trying to keep his dozen-point lead over Pat Clark from shrinking.

As exciting as the championship races will be, they are somewhat only a prelude to the weekend's main event – the Lucas Oil Challenge Cup 2011 Presented by Toyota. With the off-season ahead (no need to preserve the trucks for an upcoming race) and big purses on the table, these inter-class events mean no-holds-barred competition. The Pro 4s and Pro 2s will go head to head for $30,000 to the winner. Twenty grand is on the line for the winner of the Pro Buggy vs. Pro Lite race.

In each of the Challenge Cup races, the faster of the classes – Pro 4 and Pro Buggy – will start behind the other. For a Pro 4 or Pro Buggy to win, the drivers must work their way through the entire field of the slower class. That's in addition to any inversion in their own class. Last year it was the faster classes prevailing despite the handicap, with Pro 4 driver Kyle LeDuc winning his race, and Pro Buggy racer Doug Fortin taking it to the Pro Lite field.

In addition, each of the other classes, including Trophy Karts, will have its own race on Sunday. The Super Lites will battle for a $20,000 purse, and the Limited Buggies will race with $7,000 on the line. UTV and kart drivers will be competing for a chance to win a spot in Cory Kruseman's driving school, awarded to the top three in each class.

The last race of the season also always brings out a few people trying short course for the first time or trying a new class in preparation for next season. Rally racer Liam Doran will be at Firebird in a Pro 4 and longtime off-roader Evan Evans will be back in a truck for the first time in more than a year. The Challenge Cup racer will also bring a few non-regulars out of the woodwork.

With its dramatic step-up and either/or section, Firebird is a favorite of drivers and fans. The combination of championship battles and the unique Challenge Cup races make it a weekend not to be missed. Gates open at 9 a.m. Saturday and Sunday. For more information, see. www.lucasoiloffroad.com.