DAYTONA BEACH, Fla. — Greg Biffle thought he was in trouble with former Winston Cup champion Bobby Labonte close behind as the laps wound down Saturday night.

But Labonte ran out of gas on the last lap as Biffle and his Roush Racing crew played the fuel strategy game to perfection in the Pepsi 400, giving the rookie his first Winston Cup victory.

"I really didn't know what to do," Biffle said. "I was breathing the throttle and stepping on the brake peddle a little bit down the straightaway, trying to keep Bobby from getting too far back there and getting a run on me. I thought Bobby might get his nose under me and get me loose because I was pretty loose."

That's when Biffle's spotter said Labonte was fading, out of gas.

"He said, 'Just bring it home. You've got the race won,"' Biffle said. "What a relief because I thought when Bobby got to my bumper he'd beat me and I'd learn a lesson tonight and I'd finish second."

Labonte, who has finished in the top 10 in eight of the last nine races, said, "We had to go for it. I wasn't conserving fuel, but I wasn't using any extra, either. I didn't realize we were going to run out of gas. We gave it all we had. It's still a great finish for us."

Biffle, a former Busch Series and NASCAR Craftsman Truck Series champion, was in position to earn his first win in 24 Winston Cup races because of a spur-of-the-moment decision midway through the 160-lap race on Daytona International Speedway's 2 1/2-mile oval.

Biffle ducked into the pits to top off his gas tank under caution on lap 79. That gave him just enough to make it the rest of the way on one more stop and cost favorites Dale Earnhardt Jr. and Michael Waltrip a shot at another restrictor-plate victory.

"I don't think we had any crazy pit strategy or anything," the winner said. "What we did, I thought, just made sense. We came in and took a splash of fuel before it went green.

"I talked to (crew chief) Randy (Goss) about that. I was looking in the mirror and I thought it looked like some guys were going to come in. I asked him what he wanted to do and he said to come in. . . . It was kind of a decision we made together and it really paid off for us."

On his last stop, on lap 120, Biffle yelled at his crew over the radio because he thought they held him a half-second too long.

"But they were holding me to get that last little bit of gas in it and it paid off," Biffle said. "Bobby pitted on the same lap we did."

Jeff Burton, Biffle's teammate, running the same fuel strategy, finished second, 4.102 seconds — about 20 car-lengths — behind the winner's Ford Taurus.

The winner also gave a lot of the credit to series points leader Matt Kenseth, another Roush entry, who was running second and kept Labonte behind him until Kenseth had to pit for a splash of gas at the end of lap 156.

Kenseth got back out fast enough to finish sixth, just behind Labonte, who coasted to the finish line. Ricky Rudd finished third.

Kenseth's finish was good enough to keep him in the series lead, 180 points ahead of Earnhardt, who jumped ahead of Jeff Gordon into second place with a seventh-place finish.

Biffle got the opportunity to try a fuel economy run because the race was slowed by only two cautions for a total of 10 laps and none in the last 81 laps.

Dale Earnhardt Inc., teammates Earnhardt and Waltrip came into the race as heavy favorites, having won eight of the last 10 races at Daytona and Talladega, the two big tracks where NASCAR requires the carburetor restrictor plates to keep the cars under 200 mph.

But both of them stayed on the track when the other cars ducked in to top off for fuel and had to make an extra stop. Earnhardt appeared to have the strongest car in the field and led two times for 43 laps. Waltrip, coming up well short of his third straight Daytona win, wound up 11th.

Kevin Harvick, who started from the front row and led three times for 54 laps, also got caught by the fuel strategy and finished ninth, as did four-time Daytona winner Gordon, who was 14th.

The win was only Biffle's second top-10 finish. His best previous result was fifth at Bristol in March.

The winner, who led the last 21 laps after taking the lead when most of the fastest cars pitted, averaged 160.109 mph.

With the cars running in big packs, there is usually at least one big crash in every plate race. The big one Saturday night, involving seven cars, came on lap 74 when Kurt Busch cut down his right rear tire and slid sideways coming off turn 2 in the middle of the field.

Robby Gordon, winner of the road race two weeks ago in Sonoma, Calif., hit the brakes hard, but got hit in the rear by Mike Wallace and slammed nose-first into the wall. Pole-winner Steve Park, Joe Nemechek, Ricky Craven and Jamie McMurray also got caught up in the melee.

"We were a victim. Four times a year we race on these restrictor-plate tracks, and you have to expect it when you least expect it, and that was the case here," Craven said. "I really didn't expect that to happen on new tires among the leaders."