Helio Castroneves finally broke through for a victory Sunday at Infineon Raceway, winning for the first time in 30 races.

More important, the Team Penske star, frustrated until now with seven runner-up finishes this season, kept alive his hopes for an IndyCar Series championship as points leader Scott Dixon had one of his worst days of the season, finishing 12th.

Dixon saw his lead shrink from a seemingly comfortable 78 points to 43 heading into next week's race at Detroit's Belle Isle, the penultimate race of the season.

Castroneves and teammate Ryan Briscoe started 1-2 and finished the same way, completing an amazing weekend after losing their primary cars in a transporter fire on Wednesday and have to race in the Grand Prix of Sonoma in hastily prepared backup cars.

Castroneves was almost delirious with joy as he crossed the finish line, screaming and hollering, "Bring it home, baby."

Nicknamed Spider Man for his fence-climbing victory celebrations, the Brazilian scrambled out of his No. 3 Dallara Honda at the finish line and looked for something to climb. The best he could do was a short fence behind the pits that put him into a crowd of fans, who helped Castroneves celebrate.

"They kept telling me, `Push, push, push.' That was fun, a lot of fun," Castroneves said. "Oh my God, this is awesome. We've been close so often. We never lost faith. This is great for Detroit."

Castroneves, who started from the pole, won this one, his 13th career victory, with a perfect pit strategy. After he made the last of his three fuel stops on lap 57 of the 80-lap event, all Castroneves had to do was wait for the drivers ahead of him to make their last stops.

He took over the lead for good on lap 59 when rookie E.J. Viso pitted and easily led the rest of the way on the 2.245-mile, 12-turn road course.

Tony Kanaan and Den Wheldon, both eliminated from championship contention on Sunday, finished third and fourth, followed by Danica Patrick and Viso.