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Defending Sprint Cup Series champion Brad Keselowski is off to a great start this season, and he's hoping his momentum will continue this weekend at Auto Club Speedway in Southern California.

Keselowski, who drives the No. 2 Ford for Penske Racing, is the only competitor who has finished among the top-five in the first four races this year. He placed fourth at Daytona and Phoenix and then third at Las Vegas and Bristol. Keselowski has also led a lap in each one of those races.

He currently holds a nine-point lead over Dale Earnhardt Jr. and a 15-point advantage over Jimmie Johnson, who dropped from the top spot in the standings after his 22nd-place finish at Bristol. Earnhardt has no worse than seventh this season.

"We're off to my best start ever, and that's really cool," Keselowski said. "We can't keep our feet still. We know that Kyle (Busch) and Jimmie (Johnson) are going to continue to make their cars better. We have to keep digging and push on our stuff too."

Keselowski's start is the best for a driver in the series since Johnson began the 2005 season with four straight top-five finishes. A fifth consecutive top- five for Keselowski would be the first time that feat has been accomplished since 1998 with Rusty Wallace, who ironically drove the No. 2 car for Penske at the time.

Keselowski has not performed well in past Sprint Cup races at California, finishing no better than 18th in his four starts here. He's had good finishes in Nationwide Series events at this track, placing no worse than 10th in his last five attempts.

"We've run really well with the Nationwide car at Auto Club Speedway over the last couple of years," he said. "We don't yet have a win to show for it, but it gives me a boost of confidence, because Fontana has been one of the tougher tracks for me over the years."

Kasey Kahne has also been hot lately. Kahne began the season with a 36th-place finish in the Daytona 500 and then 19th at Phoenix but has rebounded nicely since then. He finished second at Las Vegas after leading the most laps. This past Sunday, he won at Bristol for the first time.

Kahne is presently seventh in the point standings. When the series came to Fontana one year ago, he sat 32nd in points. It was his first season with Hendrick Motorsports. Kahne went on to make the Chase for the Sprint Cup championship after winning two races during the regular season (Charlotte and New Hampshire).

"The championship is still a long ways away, but I think we're off to a much better start than last year," he said. "I feel good about that. We got a little behind at the start of (this) season and fought back clearly in the last two weeks and got back to a good spot."

This will be the first time NASCAR's new Sprint Cup car, the Gen-6, will race on a two-mile oval. The car has been getting much better reviews the past couple of weeks. It ran on a short track last week at Bristol, with Kyle Busch breaking a decade-old track qualifying record there.

"I think this new car is going to create a better race at (Fontana), a more aggressive race," Kahne said. "As slippery as Auto Club is, it's just going to make it even a little better for us."

With the Gen-6 having more downforce and better grip than the previous race car, which was used the last six seasons, it's likely we'll see record speeds posted at Auto Club Speedway.

"I think it's going to be a fun race," Johnson said. "We have a lot of racetrack to race on. We're all getting smarter about the cars."

Johnson, who hails from nearby El Cajon, Calif., has the most wins at this track with five. Jeff Gordon, who is Johnson's teammate at Hendrick Motorsports, and Matt Kenseth, in his first season with Joe Gibbs Racing, have three victories each here.

Tony Stewart has won two of the last three races at this track, including a victory in last year's rain-shortened event. Heavy precipitation after 129 of 200 laps were completed forced NASCAR officials to call the race. It was the first time a Sprint Cup event here was cut short due to inclement weather.

Forty-three teams are on the preliminary entry list for the Auto Club 400.

Series: NASCAR Sprint Cup. Date: Sunday, March 24. Race: Auto Club 400. Site: Auto Club Speedway. Track: 2-mile oval. Start time: 3 p.m. ET. Laps: 200. Miles: 400. 2012 Winner: Tony Stewart. Television: FOX. Radio: Motor Racing Network (MRN)/SIRIUS NASCAR Radio.