FONTANA, Calif. (AP) -- Kyle Busch figured he had little chance to defend his Fontana title for most of Sunday while he circled the oval in a ''mediocre'' car.
Yet his tires were just fine, unlike much of the rubber on the bumpy racetrack. And when the race came down to a two-lap sprint to the finish, Busch demonstrated his spectacular closing skills one more time.
Kyle Busch capably blocked Larson and outlasted a crowded field to win a race featuring a track-record 35 lead changes and numerous tire problems. Busch stayed out of trouble and roared up late for his second straight stunner in Southern California, following up the Las Vegas native's final-lap surge to victory a year ago.
''Holy cow, what do you expect when you've got a green-white-checkered finish and everybody has to come down pit road and put four tires on?'' Busch asked after his third career win at Fontana. ''That was 'Days of Thunder' right there. Unbelievable day.''
Busch is NASCAR's fifth winner in five races this season. He led just five laps - the fewest of his career in a win - in his Joe Gibbs Racing Toyota.
''I came off the fourth turn in disbelief that we won this thing, because we were mediocre all day,'' Busch said. ''It was really weird for us, not a race that we're typically used to. But now there's a load off your shoulders that you can go out the rest of the season and race the way you want to.''
He also got a thrill from outlasting Larson, the 21-year-old rookie in the No. 42 Chevrolet for Chip Ganassi Racing.
''I guess you couldn't ask for more, but I was surprised to get up there late in the race,'' said Larson, who held off Busch to win the Nationwide race Saturday. ''We were probably a 12th-place car for most of the day.''
Kyle Busch pointed out his window at Larson after Sunday's finish, pumping his fist in approval.
''What a shoe that boy is,'' Kyle Busch said of Larson.
Five more things to remember from Fontana's big finish:
SO CLOSE: Jeff Gordon drove the field twice and was in position for his first win of the season until Clint Bowyer's spin with two laps to go sent the race into overtime. From there, he faded badly on the two-lap sprint to the finish and wound up 13th despite having one of the strongest cars in the field.
''The closing laps were pretty much typical restart for me,'' said the four-time champion, who has struggled for several years on restarts.
Gordon overcame an early speeding penalty and was one of several drivers who missed the entrance to pit road on an early stop because the red light signifying that pit road was closed was on when they passed. It forced him to drive hard to put himself in the lead before Bowyer's spin. He regretted the final finish because of the effort he and his Hendrick Motorsports team put in Sunday.
''They gave me the most incredible race car and it is just so disappointing for it to end like that,'' Gordon said. ''I hate that the caution came out.''
SHREDDED TREAD: Jimmie Johnson, Clint Bowyer, Kevin Harvick, Carl Edwards, Brad Keselowski and Dale Earnhardt Jr. were among the drivers who had problems with their tires, yet manufacturer Goodyear didn't absorb much heat from the drivers.
The problems likely were the latest effect of NASCAR's new aero rules, which are producing higher speeds that lead to extra stress on the tires - particularly on the bumpy asphalt on Fontana's back straightaway, which already wears out tires aggressively. NASCAR also loosened rules on tire pressure.
''By no means is this a problem for Goodyear,'' Kurt Busch said. ''It's just a thumbs-up for NASCAR for allowing teams to get aggressive in all areas.''
Those problems might frustrate pit crews, but they can also lead to phenomenal racing, as the sellout crowd on its feet for the finish could attest.
HAMLIN SIDELINED: Denny Hamlin never got a shot at the redemption he craved after last season's final-lap crash with Joey Logano at Fontana left him with a broken vertebra.
About 30 minutes before Sunday's race, Joe Gibbs Racing said Hamlin was headed to the hospital for tests on a sinus infection. He was expected to stay overnight in the Los Angeles area.
''It's not just a headache. It's a lot more serious than that. He was actually losing vision his eye,'' crew chief Darian Grubb told MRN.com and NASCAR.com after the race.
SMOKE SIGNALS: Don't count out Tony Stewart just yet. After a lousy start to the Sprint Cup season, Smoke has posted back-to-back top-five finishes, following up his fourth-place finish at Bristol by coming in fifth. The 2012 Fontana champion had a shot at another win late, and Kurt Busch particularly enjoyed racing his boss for position in the final two laps.
UNIFORM CAUTION? For the second straight week, NASCAR had a problem with the caution light on pit row - but this one was more hilarious than detrimental.
Several drivers complained during an early pit stop that the red light was on, indicating pit road was closed. Robin Pemberton, NASCAR's vice president of competition, was told that the official in charge of displaying the flag got his uniform caught in a hole in a fence and couldn't move, preventing him from flipping off the red light.