Jimmie Johnson Jimmie Johnson

Any fans still wallowing in shock over Dale Earnhardt Jr. missing the cut for the 2007 Chase for the Nextel Cup had best get over it. NASCAR's postseason gets under way this Sunday with the Sylvania 300 (1 pm/ET, ABC), in Loudon, New Hampshire, and it looks to be the most jarringly competitive last 10 races since the Chase format began in 2004. The field of 12 (an increase this year from the customary 10) is rife with former winners, led by defending champ Jimmie Johnson, who's entering the Chase with great momentum.

Johnson won the last two races of the "regular" season — not to mention notching top-five finishes in five of the last six contests. Still, he must contend with fellow ex-titleholders Jeff Gordon, Tony Stewart, Kurt Busch and Matt Kenseth. Stewart, who won his second Cup trophy in 2005 but missed the Chase cut last season, is understandably hungry, and after not qualifying last season, he feasted on the field, winning three of the last 10 races.

Still, it's hard to argue with Johnson. "Momentum is important in this sport in particular, and he has to be looked at as a favorite," says Dr. Jerry Punch, an ESPN/ABC NASCAR analyst who'll be covering the last 10 races, beginning Sunday afternoon at the New Hampshire International Speedway. Adds Punch's coanalyst Rusty Wallace, "Jimmie's very good at the short tracks, and you're coming up [on one] at Loudon; and he's also won at Dover," site of the Sept. 23 race. In three years since the Chase format began, in fact, nobody's come close to Johnson's Chase win total of seven.

But the theme of this Chase may well be guys out to prove something. Carl Edwards, a lock for the Busch-series title, wants both championships. Gordon, who led the standings for most of the season, hasn't won a Cup title since 2001 and he's tired of all the talk that he's never going to win his fifth. Busch would love to be the first driver to win titles for two different team owners since Terry Labonte in 1996; his brother Kyle would get some vengeful glee from beating fellow Hendrick Motorsports Chasers Johnson and Gordon before shipping out next year to Joe Gibbs Racing. Kevin Harvick, this year's Daytona 500 champ, is looking to rebound from an otherwise subpar season. And Denny Hamlin, last year's top rookie and winner of July's race in Loudon, wants to prove he's more than just the second-best Gibbs driver.

To do that, he'll have to go through teammate Stewart, who still leads the Chase field in angry determination. "I remember in 1992, Dale Earnhardt Sr. and I both missed the top 10; we got our butts kicked and we didn't like it," Wallace recalls. "That's what happened to Tony Stewart last year. Dale and I both came back with a vengeance the next year; he won the title and I won 10 races and finished second. I think Tony's the guy that's gonna win this title."

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