LOUDON, N.H. (AP) - Kurt Busch had a not-so-secret weapon ready for the NASCAR Nextel Cup race at New Hampshire International Speedway.

While others struggled to figure out their setups Sunday after rain washed away qualifying Friday and practice Saturday, Busch simply jumped into the No. 97 Roush Racing Ford that he won in at the track in July and ran off with another win.

''We pulled the car out from underneath the car cover and ran it,'' Busch said, grinning broadly after leading 155 of 300 laps on the 1.058-mile oval. ''Limited track time definitely helped us today."

The performance in the Sylvania 300 could not have come at a better time, with Busch jumping from seventh to a tie for the series lead with Dale Earnhardt Jr. after the first race of NASCAR's new 10-man, 10-race championship showdown.

He's tied for the top spot, only the third time in Busch's four-year Cup career that he has been on top of the points.

He led for one race after finishing second at Rockingham in February 2003 and again for one race after finishing sixth at Texas in April.

Matt Kenseth, the 2003 series champion, was second, crossing the finish line 2.488 seconds - about 20 car lengths - behind his Roush Racing teammate.

''I knew we probably weren't going to catch him,'' Kenseth said. ''Kurt had a great car and was getting through the center of the corner really fast. I tried to keep up with him as long as I could.

''We were set up a little different than Kurt. We couldn't do anything with him, but I'm pretty happy with the way it went.''

Kenseth won the Cup championship last year in a relatively boring runaway that helped NASCAR in its decision to change the points format.

Team owner Jack Roush was ecstatic over the strong start for the teammates in the title battle, especially after being so disappointed the previous week at Richmond when Busch ran out of gas a while leading eight laps from the finish.

''A lot of cars fell out and I think it's a heartbreak day for a lot of teams, but we were lucky,'' Roush said. ''That was great that they had plenty of gas today and we didn't have any problems on the racetrack.''

With the lineup set by owner points because of the qualifying rainout, all the drivers in the championship battle started up front, and seven finished among the top 13.

Earnhardt, who needed a relief driver at this track in July after being burned in a sports car crash the previous week, ran strong Sunday and finished third. If the championship was determined after Sunday, Earnhardt would win the tiebreaker based on his four wins this season.

''My car was pretty good all day,'' said Earnhardt, who started the day in third. ''We guessed right on the setup. We didn't have a good enough car for a top-five finish, so I'm pretty happy about that.''

He was followed by rookie Kasey Kahne, Jamie McMurray, Joe Nemechek, Jeff Gordon, Elliott Sadler, Michael Waltrip, Kevin Harvick, Jimmie Johnson, Sterling Marlin and Mark Martin.

Gordon, Sadler, Johnson and Martin, another Roush driver, are all among the title contenders. Gordon, who began the day with a five-point lead over teammate Johnson, is now third, nine points behind the leaders and one point ahead of Kenseth. Johnson fell to fifth, 30 points back.

Three of the contenders ran into big trouble Sunday.

The action got started early when Greg Biffle spun former New Hampshire winner Robby Gordon into the wall, bringing out the first caution of the day on lap 17.

On lap 64, Robby Gordon ignited a multicar crash, drawing a two-lap penalty from NASCAR after hitting Biffle from behind. Tony Stewart tried to go around Biffle and Jeremy Mayfield, and all of them wound up damaged.

Mayfield, who drove his way into the Chase with a victory at Richmond, and 2002 series champion Stewart got the worst of it. Both had to spend considerable time in the garage for repairs and wound up dropping out of the race early, with Stewart finishing 39th and Mayfield 35th.

An engine failure knocked Ryan Newman out late in the race after he had briefly worked his way into the lead.

The day began with the top 10 separated by a total of just 45 points. Sunday's problems left the trio far behind Busch and Earnhardt, with Stewart 124 points back, Newman 136 out and Mayfield 142 behind.

''To try to make up that amount of points in nine more races is virtually impossible,'' Stewart said. ''I can promise you one thing, though. This team has never given up and they're not going to give up now.''