ESPN IndyCar

For the third consecutive year, the IndyCar Series championship will be decided in the season finale at Chicagoland Speedway in the PEAK Antifreeze and Oil Indy 300 (Sunday, 3:30 p.m. ET, ABC). But this year's title chase between Scott Dixon and Helio Castroneves isn't likely to be as tense as the battles in '06 and '07 when the drama played out literally to the last corner of the last lap.

With six wins and a near-record number of laps led, Dixon has dominated the 2008 season. Yet despite having only one victory, Castroneves still has a shot at the crown, thanks to no fewer than eight second-place finishes in 15 starts.

The Brazilian and his No. 3 Team Penske crew are also riding a wave of momentum. By dominating the last two races, Castroneves has cut Dixon's advantage from 78 points to 30.

Still, the odds are stacked in favor of the New Zealander, who drives the No. 9 car for Target Chip Ganassi Racing. Even if Castroneves scores maximum points Sunday by winning and leading the most laps, all Dixon needs to do is finish eighth.

His career average finish at Chicagoland Speedway in five starts is 6.4, and he has finished second in his past three races at the 1.5-mile speedway outside Joliet, Ill. In 2007, he lost the championship there to Dario Franchitti when his leading car ran out of fuel on the last lap.

"It's been a mixed bag in the way of how we've done there, and to never have won there is definitely frustrating," Dixon said. "We're hoping that we can definitely turn that around this weekend. But there's a lot of other people that are going to be trying to do the same thing."

"I think Chicago's going to be very tough," he added. "It's one of those circuits that provides great racing, and it's definitely nail-biting for a championship race, which is exactly what the fans want and everybody that's watching. I guess they'll definitely get that."

Dixon has been at his best on 1.5-mile tracks like Chicagoland this year. He has led 522 out of 1,028 laps (50.8 percent) on the way to victories at Homestead-Miami Speedway, Texas Motor Speedway and Kentucky Speedway. He led the most laps at Twin Ring Motegi and Kansas Speedway but came away with top-5s instead of wins.

If Dixon can stay within sight of Castroneves on Sunday, he'll claim a second IndyCar title to go with the one he won in 2003, his first year in what was then an all-oval series.

"The mile-and-a-half ovals, I think throughout this year, have been very tough," Dixon said. "[With] almost 10 more cars on the track than we had last year, if you make any little mistake, it makes it that much worse. We still definitely have to finish extremely well. But I'm looking forward to it. I can't wait to get there."

The Penske and Ganassi teams have combined to lead 387 out of 400 laps at Chicagoland over the past two years. After Ganassi dominated the 2006 race, Penske rebounded to control most of last year's contest, and the team used one of its valuable test days at Chicagoland earlier this week in an effort to make sure Castroneves and Ryan Briscoe run at the front.

"We've had rather mixed results on the 1.5-mile ovals over the past several seasons, so we're going to make sure we stay focused and work hard to be competitive this weekend," Castroneves said. "Despite these struggles, we've done fairly well at Chicagoland Speedway. I've earned four top-4 results since 2002, so hopefully this will be my year to climb the fence in Illinois.

"We're still in the hunt for the championship, but we're clearly the underdog," he added. "It's going to take a strong finish and a little luck for us to clinch this championship. I know that Team Penske will give me what I need to get the job done, so we'll just hope for the best."

Outside of the championship battle, here's what to watch for this weekend:

• A victory for Scott Dixon would establish an IndyCar Series record (1996 to present) with seven. Dan Wheldon also won six races in 2005. If Dixon leads more than four laps, he will break Tony Kanaan's 2004 record of 889 laps led in a single season.

• This will be Wheldon's final outing for Target Ganassi Racing after three years with the team. Wheldon's victory at Chicagoland in 2006 tied him with Sam Hornish Jr. on points, but the American was declared series champion on a tiebreaker.

• Wheldon is set to replace Vitor Meira at Panther Racing in 2009, so this likely will be the Brazilian's last outing for his current team unless sponsorship is sourced for a second car.

• The 28-car entry at Chicagoland is the largest field outside of Indianapolis for the unified IndyCar Series. Tomas Scheckter will make his sixth start of the season for Luczo Dragon Racing, while Sarah Fisher Racing is set to make its second appearance. A.J. Foyt Racing is running a second car for hot prospect Franck Perera.

• Conquest Racing confirmed that Champ Car veteran Alex Tagliani will complete the season in the No. 36 car normally driven by Enrique Bernoldi. Bernoldi injured his thumb in a practice crash at Infineon Raceway and withdrew midway through the Detroit Grand Prix weekend.

Although he did not finish, Tagliani turned the sixth-fastest lap of the race, and Conquest owner Eric Bachelart was thrilled with the job the French-Canadian did on short notice.

"It seemed like we got more information in 40 minutes from Alex than we got all year from two rookies!" Bachelart said. "Unfortunately, Enrique's injury is not healing as fast as we thought and would've liked, and with Alex doing such a great job last weekend it was an easy decision to keep him in the car for Joliet."

John Oreovicz covers open-wheel racing for National Speed Sport News and ESPN.com.