SONOMA, Calif. — Helio Castroneves didn’t want to let Team Penske down.

Five days after one of the team’s trucks caught fire during the long trek from its race shop in North Carolina to California, badly damaging the primary cars of Castroneves and Ryan Briscoe, the teammates drove their hastily prepared backup cars to a 1-2 finish in the Grand Prix of Sonoma.

“In my perspective, it’s a great and special week for us,” said Castroneves, whose victory ended a 29-race winless streak. It also put him right back into the IndyCar Series championship battle with points leader Scott Dixon, who appeared to be in control until finishing 12th on Sunday.

“It’s like all the hard work, it paid off, unexpected hard work,” said Castroneves, who won for the first time since taking the checkered flag at St. Petersburg on April 1, 2007.

Despite the frustration of seven runner-up finishes, and the fact that he had never led a lap at Infineon Raceway, Castroneves said he had a feeling that Sunday could be his day.

Known as Spider Man for his fence-climbing celebrations, Castroneves acknowledged that he checked out the best place to make his climb — just in case.

“I did, actually,” Castroneves said. “There were photographers there and I told them exactly where I was going to go. I said, ’Right there. Make sure you wait for me there.’ It’s just a positive attitude.”

Meanwhile, Dixon suffered through one of his worst days of the season and 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, who led four times for 51 of the 80 laps, was almost delirious with joy as he crossed the finish line, screaming and hollering, “Bring it home, baby.”

Living up to his prerace promise to those photographers, the Brazilian scrambled out of his No. 3 Dallara Honda at the finish line and ran to the short fence behind the pits. He quickly climbed it and found himself surrounded by admiring fans.

Castroneves then jumped back down to the track and sprinted back to his team, joining them in a group hug.

“They kept telling me, ’Push, push, push.’ And I was pushing to the limit,” Castroneves said. “There was nothing left out there.

“That was fun, a lot of fun. Oh my God, this is awesome. We’ve been close so often. We never lost faith. This is great for Detroit.”

Tim Cindric, president of Team Penske and the man who manages the races for Castroneves, said, “We would not have won this race if Helio hadn’t driven the wheels off it when he needed to. ... We will keep going and see where we end up at the end of the year.

“I think our approach next weekend is the same: We go for broke. That’s the only thing that is going to get us where we need to be.”

As happy as Castroneves and his team were, Dixon was just as frustrated.

“It was definitely a bad day. We lost a ton of points,” the New Zealander said.

“This is a race that’s very tough. Unfortunately, we got the bad end of the stick. I guess we just need to shrug it off and come back strong next week.”

Team owner Chip Ganassi said Dixon is still the favorite to add another title to the one he won in 2003.

“I think if Helio wins the next two (races), we just have to place fourth, so we should be able to do that,” Ganassi said. “We just have to stay behind him. We’re OK. We have a long way to go yet.”

Castroneves, who started from the pole Sunday, won this one, his 13th career victory, with a perfect pit strategy and a very strong car.

He gave up the lead on his first stop on lap 17 of the 80-lap event and regained the top spot when the last of the leaders, rookie E.J. Viso, finally pitted on lap 36. By the time Castroneves pitted again on lap 44, he had built a lead of more than 16.5 seconds over Briscoe.

That put the two-time Indianapolis 500 winner right where he wanted to be. After he made the last of his three fuel stops on lap 57, 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 Viso pitted and easily led the rest of the way on the 2.245-mile, 12-turn road course, beating Briscoe to the finish line by 5.29 seconds — about 30 car lengths.

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

When Dixon made his second of three stops, also on lap 44, he was third, just behind Briscoe. But Dixon came out of that stop deep in the pack and was never in contention again.

“I’m not upset with anybody, particularly. We just did absolutely nothing right,” said Dixon, who has a record-tying six wins this season and had only two finishes worse than fourth until Sunday. “Everything we did was wrong.”