FONTANA, Calif. — When dark clouds ominously obscured majestic Mount Baldy north of Auto Club Speedway early in Sunday's race, NASCAR's drivers all realized they were probably in for a short day on a long track.
Nobody did a better job racing until the raindrops fell than Tony Stewart.
Stewart got his second NASCAR victory of the season when rain shortened the race at Auto Club Speedway by 71 laps, extending the defending Sprint Cup champion's unusually strong start.
Kyle Busch finished second, and Dale Earnhardt Jr. added to his good start to the season in third.
"You hate to have it end with rain like that," Stewart said. "But we've lost some that way, and we didn't back into the lead."
Stewart has won seven of the last 15 races, including Las Vegas last month, in a remarkable stretch of dominance for a driver who rarely gets rolling until summer.
Although Stewart sees nothing special about his approach to the new season, he's clearly focused. Stewart and new crew chief Steve Addington didn't mention the rain to each other until moments before it hit one end of the 2-mile oval, but they had already done the work necessary to win.
"It's been nice to get off to a good start this year the way we have," said Stewart, who has been even more impressive this year despite firing crew chief Darian Grubb last December. "The history shows the last 13 years, we haven't had the strongest start the first third of the year, but I'm really excited about the start we've got going. Daytona was probably our weakest race, and I know I made decisions trying to make things happen and it didn't work out. I'm really proud of what Steve and all our guys have done."
Stewart's Chevrolet passed Busch 44 laps before the race was stopped when the looming rain clouds finally burst and halted a race run entirely on green flags to that point. Although a few drivers weren't happy when the race was called off after a delay of just over 30 minutes amid steadily worsening rain, Stewart collected his 46th career win and his second at Fontana.
Defending race winner Kevin Harvick was fourth, and Carl Edwards was fifth. Greg Biffle, Edwards' Roush Fenway Racing teammate, finished sixth and kept a seven-point lead on Harvick atop the points standings.
"We had a great race car there from the start of the race," said Busch, who started second alongside teammate Denny Hamlin and took the lead on the second lap. "We led a lot of laps. I just wish we led 30 more."
INDYCAR: At St. Petersburg, Fla., Helio Castroneves used a bold pass of Scott Dixon to win the IndyCar season opener through the streets of St. Petersburg.
Castroneves' victory Sunday comes as the Brazilian is attempting to rebound from the worst year of his career. He went winless last season for the first time in IndyCar and finished 11th in the points.
The Penske Racing driver gave Chevrolet a win in its debut race. The engine manufacturer returned to IndyCar after a six-year absence.
Dixon finished second for Target Chip Ganassi Racing in a Honda. He was also runner-up to Castroneves in both 2006 and 2007.
Pole-sitter Will Power failed to overcome a decision to pit early for gas and finished seventh.
Former Formula One star Rubens Barrichello was 17th in his IndyCar debut.
FORMULA ONE: At Sepang, Malaysia, Ferrari's Fernando Alonso won a dramatic Formula One Malaysian Grand Prix on Sunday, giving the Italian team one of its more unlikely victories in its long history.
In a race that was stopped for 51 minutes because of rain, Alonso looked like he'd be overtaken by Sauber's Sergio Perez until the Mexican ran off the track with six laps to go, giving the Ferrari enough of a gap to hang on.
Ferrari had been considered to be in crisis after a poor start to the season, but a superb display of wet-weather driving gave Alonso a memorable victory. Perez's second-place finish was Sauber's best-ever.
Pole-sitter Lewis Hamilton of McLaren finished third ahead of Red Bull's Mark Webber and Lotus' Kimi Raikkonen.