Yamaha’s James Stewart and Suzuki’s Chad Reed will continue their Supercross rivalry this weekend at the 2009 US Open. Two nights of racing action will feature the top off-road riders in the world, racing upon special invitation for $100,000 in a special one-class-one-champion format.

The rivalry between the top two contenders will take center stage, but there are other heavy hitters looking to surprise the Vegas crowd. This year will also feature a couple tweaks to the format to stir up some interest, including head-to-head heat matches and a mechanic competition that could score an extra point apiece for the winner. Here’s what to watch for this weekend:

Stewart vs Reed

There’s no denying the Stewart/Reed rivalry is unfinished. Don’t forget the last time the two came together on the race track, they literally came together! It was the 2009 Supercross finale, with Reed trying to punt the future champ off the track in a desperate bid win the title – falling short to the Yamaha pilot. That move, of course, a little payback as Reed suffered a similar fate the race before at the hands of Stewart’s teammate, Kyle Chisolm, effectively taking him out of the championship hunt.

Since that dramatic encounter, the tension has been simmering. Stewart sat out the 2009 MX season, which Reed pounced on - taking the title without much competition. Did we mention MCUSA SX correspondent Steve Bruhn reporting that Reedy threw down some smack at the Motocross of Nations press conference, calling out Stewart for not representing the US?

Yeah, you could say there’s some unfinished business between the two. Luckily the US Open is the perfect venue to hash it out. No worries about protecting points or long-term championship strategies – just two races with a start and a finish. As if there needed to be more incentive, if either rider wins they’ll up their career US Open titles to three, matching them with Ricky Carmichael for the most all time (unfortunately RC couldn’t be enticed out of his two-wheeled retirement…)

Hopefully Reed and Stewart will deliver a pair of memorable races worthy of the hype!

Dungey MXoN Champ

Unfortunately for Reed and his aforementioned dig at the MXoN, the American “B-Team,” sans Stewart, ended up taking its fifth consecutive title at the prestigious international event – Australia not even on the podium. And the biggest reason for the American win? Try Suzuki’s Ryan Dungey, who is sure to have a little swagger in his step when he strides into the MGM Grand.

The golden boy from Minnesota has graduated from two-fiddies in fine fashion scoring the overall at the MXoN aboard the RM-Z450. Officially wearing 450 britches now, can Dungey measure up with Stewart and Reed under the lights? Something says J Stew might show his younger colleague that star 450 spot on next year’s MXoN isn’t up for grabs.

Ezra Lusk Returns

Coming out of retirement for the US Open is former Supercross Lites champ and 12-time SX winner Ezra Lusk, who will ride a MB1/Tokyo Mods Suzuki. Lusk, after retiring in 2004, competed on the amateur tennis circuit. So what can fans expect from Lusk after trading a genteel racket for a knuckelbusting MX ride? That’s what he’d like to know.

“I am not sure what to expect at this race,” said Lusk in a press release. “I never stopped riding, just racing, so I have had plenty of seat time and excellent training. This is a great opportunity for me to showcase what I have. It’s going to be tough just making it to the main event, but this is a unique race. History shows that the fastest guy doesn’t always win the overall.”

Supercross Stars

Glancing down the invite list, the confirmed riders are surprisingly sparse from the established Supercross roster – at least the usual suspects, many of whom are struggling with injuries. Or in Jason Lawrence’s case, reasons of a more department of corrections nature...

There are, however, some regulars that will be in attendance. Honda rider Davi Millsaps and privateer Kevin Windham are in the mix, as are Reed’s fellow teammate and countryman Michael Byrne. Trey Canard is also on the confirmed list, the 250 champ mixing it up with the varsity crew starting on Friday night.

The US Open main events will run on two separate track designs, one Friday night and the other Saturday. The combined results will determine the US Open winner.

The 2009 US Open Supercross will air on CBS October 17th at 1:30-3:00 p.m. ET.