Updated

The 10-race Chase begins this weekend at Chicagoland Speedway, as 12 drivers begin their battle for the 2012 Sprint Cup Series title. The IZOD IndyCar Series will decide its championship in the season-finale at Auto Club Speedway in Southern California.

NASCAR

Sprint Cup Series

Geico 400 - Chicagoland Speedway - Joliet, Ill.

Let the 10-week madness in the Sprint Cup Series begin.

Sunday's 400-mile race at Chicagoland Speedway kicks off the 2012 Chase for the Sprint Cup championship. It's the second straight year Chicagoland hosts the opening round in the playoffs. New Hampshire started the Chase each year from 2004-10.

Just 12 points separate top-seed Denny Hamlin from 12th-place Jeff Gordon.

Tony Stewart begins his title defense only three points in back of Hamlin. When the series came to Chicagoland one year ago, Stewart started the Chase in the ninth seed and had yet to win a race during the season. He had struggled during the summer months and just squeaked into the playoffs.

Delayed one day due to rain, Stewart prevailed in the Chase-opener at Chicagoland. He gambled on fuel in the late going and held off Kevin Harvick during the closing laps to claim his first victory of the season. Stewart won again the following weekend at New Hampshire.

Stewart went on to win at Martinsville, Texas and the season-ending race at Homestead. He finished the Chase in a points tie with Carl Edwards but claimed his third championship in NASCAR's premier series by virtue of his five wins.

"It's hard to predict what's going to happen," Stewart said. "I wouldn't have predicted last year was going to end up like it did, and I wouldn't have predicted this year was going to be the way it is right now. I'm just trying to take it a race at a time right now."

Stewart finished fourth in last Saturday night's race at Richmond and ended the regular season 10th in the point standings. With victories at Las Vegas, California and Daytona earlier this year, Stewart earned nine bonus points to start the Chase.

But Stewart has concerns heading into the final 10 events. He had finished no better than 19th in four straight races before ending his streak of bad luck with a top-five run at Richmond.

"I'll be honest; I'm not happy with any part of my program right now," he admitted. "We have a lot of work to do."

Stewart is the only driver in the postseason that has won at every Chase track. In fact, he has won at all tracks on the current Sprint Cup schedule, except Darlington and Kentucky. The series ran at Kentucky for the first time last year.

Stewart leads all drivers with three victories at Chicagoland. His other wins there came in 2004 and '07.

Gordon, Harvick and Dale Earnhardt Jr. are the only other Chase drivers who have won at Chicagoland in the past. Harvick won the first two races there from 2001-02. Earnhardt Jr.'s victory at this 1.5-mile track came in 2005, while Gordon's win there occurred in 2006.

Earnhardt Jr. and Harvick qualified for the Chase by finishing the regular season in the top-10 in points. Gordon earned his way into the playoffs with the second and final wild card spot.

"You want to come out of the gate strong and get the best possible result you can," Gordon said. "If that's a win, great. If that's fifth, great. A lot can happen during the Chase. To me, 10 weeks is a lot of racing."

Hamlin is hoping to return to his winning ways at Chicagoland. He had been on roll by winning at Bristol and then Atlanta. Hamlin put on a dominating performance for most of the race at Richmond, leading 202 of the first 300 laps. But pit strategy during the final 100 laps put him out of contention to win, as he finished 18th.

"Now it's time to put your game face on and see what you got," Hamlin said. "We're excited about going to Chicago and hopefully getting a good kickoff to the Chase."

Hamlin's best finish in six races at Chicagoland is fifth, which came in 2009. He finished 31st there last year.

"When I start my engine for the very first Chase race, I'm not thinking about Homestead, and I'm not thinking about a championship. I'm thinking about that race, and that's the attitude I'm going to have," Hamlin said.

Forty-seven teams are on the preliminary entry list for the Geico 400.

Nationwide Series

Dollar General 300 - Chicagoland Speedway - Joliet, Ill.

With eight races to go, only one point separates Elliott Sadler from Ricky Stenhouse Jr. in the Nationwide Series standings.

Stenhouse's second-place finish compared to a 12th-place run for Sadler last Friday at Richmond allowed Stenhouse to trim 11 points off of Sadler's lead.

Now the title battle between the two moves on Chicagoland Speedway. Sadler is hoping to put Richmond behind him with another victory at Chicagoland. When the series last competed there in July, Sadler grabbed the lead during a late- race round of pit stops and then held off Stenhouse and Justin Allgaier in a green-white-checkered finish for the win.

"I feel like I let the team down (at Richmond), but we are all hungry and have no other choice but to get back up and fight," Sadler said. "I've said it several times this season but these are the races and circumstances that make a championship team. We'll regroup, get more fired up and head to Chicagoland Speedway."

Sadler and Stenhouse have four wins each this season.

Stenhouse has been hot lately, finishing either first or second in the last three races. He won at Atlanta.

All but two of the remaining eight races will be contested on 1.5-mile tracks, beginning with Chicagoland. Kentucky (Sept. 22), Charlotte (Oct. 12), Kansas (Oct. 20), Texas (Nov. 3) and Homestead (Nov. 17) are the other mile and a halfs.

"Our 1.5-mile track program has been stout this year," Stenhouse said. "Earlier this year, we sat on the pole and finished second (at Chicagoland). After leading 135 laps, we felt like we let that race slip away, so we are looking to redeem ourselves this weekend. We currently sit one point out of the lead in the championship battle, so we need a strong finish."

Dover (Sept. 29) and Phoenix (Nov. 10) are both one-mile tracks.

Rookie Austin Dillon comes to Chicagoland 30 points behind his Richard Childress Racing teammate, Sadler, while Sam Hornish Jr. trails the leader by 50 points.

Forty-five teams are on the preliminary entry list for the Dollar General 300. Kurt Busch, Brad Keselowski, Joey Logano and Paul Menard are those Sprint Cup Series regulars competing in this event. Keselowski is the defending race winner.

Camping World Truck Series

American Ethanol 200 - Iowa Speedway - Newton, Iowa

After taking a break last weekend, the Camping World Truck Series resumes its schedule on Saturday night at Iowa Speedway.

Timothy Peters holds only a six-point lead over James Buescher, while rookie Austin Dillon trails by just nine points. Parker Kligerman isn't too far behind in fourth-place (-21).

After winning the Aug. 22 race at Bristol, Peters had a 17-point advantage over Buescher. Peters led all 204 laps in that event.

"There have been several times this year where we've come so close to a win, and leading all the laps at Bristol was huge for us, but Iowa was special for me because it kind of reminded me of my late model days," Peters said. "We sat on the pole. We had a really good truck, and we won the race."

One week after Bristol, Buescher finished third at Atlanta and trimmed 11 points off of Peters' lead. Peters placed 13th there.

Peters has been the points leader for the last seven races. The Red Horse Racing driver has sat no worse than second in the standings since the season began in February at Daytona.

"My crew chief, Butch Hylton, has been around for a while and knows how to lead our crew through any situation that comes our way," Peters said. "Basically, we look at it as our next practice or next race is the most important thing to our team. You can't look too far ahead or get all wrapped up in what's going on, because that's when bad things happen.

"When we led every lap at Bristol and won, we had discussed before the race that we weren't going to worry about points. We were just going to go out and win the race. And that's what we did. That mentality has really helped us so far and hopefully will carry us into Homestead in November."

Peters comes to Iowa with an opportunity to score a season-sweep there. A second date for this 0.875-mile racetrack was added to the 2012 Truck Series schedule. If Peters takes the checkered flag at Iowa this weekend, he will become just the fifth driver in the series to win both races at a track in the same season.

Jack Sprague was the first driver in trucks to record a season-sweep, doing it in 1996 at Phoenix. Brendan Gaughan won four consecutive races at Texas from 2002-03. Ron Hornaday Jr. won the two Texas events in 2008. And Mike Skinner claimed victories in both races at Martinsville in 2007.

A season-sweep in trucks is a rarity, with just four tracks hosting more than one race a year -- Iowa, Kentucky, Martinsville and Texas.

Thirty-eight teams are on the preliminary entry list for the American Ethanol 200. No driver is attempting the Chicagoland/Iowa combo this weekend.

IZOD INDYCAR SERIES

MAVTV 500 - Auto Club Speedway - Fontana, Calif.

After 14 races have been completed within the last six months, the 2012 IZOD IndyCar Series season will conclude on Saturday night at Auto Club Speedway in Fontana, Calif.

It's the first time IndyCar has competed at this two-mile oval in seven years. The series ran there each year from 2002-05 before it was dropped from the schedule.

This will also be the seventh straight season the IndyCar championship is decided in the season-finale. Will Power currently holds a 17-point lead over Ryan Hunter-Reay. Helio Castroneves, who is Power's teammate at Team Penske, is 52 points out of the lead, while Scott Dixon trails by 53. Castroneves and Dixon are still mathematically in contention, but both drivers are very long shots to win the title.

Power is no stranger to being in the middle of a tight fight heading into the last race of the season. For the past two years, Power held the points lead entering the season-finale but lost the championship both times to Dario Franchitti.

The third time could be the charm for him.

"It's going to be obviously a tough race, 500 miles," Power said. "I've been in this position for the last two years. We just focus on the job that we have to do to execute on the day. The rest will work itself out. Either we'll be champion or we won't."

In his third year with Andretti Autosport, Hunter-Reay is having a career-best season with four wins to his credit. He has finished seventh in points the past two years.

"I definitely like the position we're in, chasing," Hunter-Reay said. "We've been doing that for most of the year. I think we've been getting better at it.

"We need to go out and focus on winning. That's really what it's going to be about. Five hundred miles is a long race. The race that we have in the first 250 is going to be a lot different than we have in the last 250. We could see a lot of comers and goers. It's going to be changing the entire time."

Hunter-Reay's path towards a possible championship has not been an easy one. After finishing 24th in Aug. 5 race at Mid-Ohio and then 18th in the Aug. 26 event at Sonoma, Calif., it looked as though Hunter-Reay's title hopes were fading away, as he trailed Power by 36 points.

But Hunter-Reay bounced back earlier this month by winning the Grand Prix of Baltimore. Power finished sixth in that race.

"It hasn't been easy," Hunter-Reay admitted. "Right when things looked like they were going exactly our way, other situations would come about, like the situation with Sonoma, then some of the reliability issues we had at Mid-Ohio. These things happen in racing. It's part of it. Will has seen that in his runs for the championship as well. Right when things start to look like they're heading in the right direction, you could be thrown a curve ball."

While the road/street courses have been his strong suit, Power has struggled on the ovals throughout his IndyCar career. His best finish in the first four oval races this season is eighth, which came in June at Texas. His other finishes on the ovals in 2012 have been: 28th (Indianapolis), 12th (Milwaukee) and 23rd (Iowa).

Power's only win on an oval came last year in the second race of a doubleheader at Texas.

Two years ago, Power crashed with 57 laps remaining in the season-ending race at Homestead, Fla. He lost the championship to Franchitti by just five points.

In what turned out to be the last race of the 2011 season, Power came to Kentucky Speedway with an 11-point advantage over Franchitti. Power, who started on the pole and led the first 48 laps, made contact with Ana Beatriz while entering his pit stall during the first round of stops. He had to pit several times for repairs and ended up finishing 19th.

Las Vegas had been scheduled as the season-ending race last year. But the event was canceled after a horrifying 15-car wreck that claimed the life of Dan Wheldon occurred in the early going. Power was caught up in that wreck and suffered a compression fracture of his fourth thoracic vertebra. IndyCar officials ruled the Las Vegas event incomplete and championship points would include races up through Kentucky, which was held two weeks earlier.

Power is hoping he'll have an incident-free race at Fontana.

"Maybe it will be the first last race that I finish, because every year I get crashed out," he said. "So I'm determined this time to just finish the last race and finish it as the leader of the championship."

Last week, eight drivers, including Power and Hunter-Reay, tested the new chassis-engine package at Fontana. Most IndyCar teams participated in a second round of testing there on Wednesday.

"I haven't driven around the track since 2003, but I can tell you the track has picked up some 'character' since then," Hunter-Reay said.

With the 500-mile race beginning in daytime and concluding at night, the change in track temperature will be a huge factor.

"That's going to be interesting," Power said. "As it cools down, we're going to gain grip. I see it probably a little bit more like Texas. I think Indy was too easy this year. It was just wide open, especially in qualifying. Based on tests, with the bumps and everything, I can't see that."

Twenty-six teams are on the entry list for the MAVTV 500.