SONOMA, Calif. -- Team Penske's Will Power seems to be on his way to winning his first IndyCar championship after finishing second to teammate Ryan Briscoe at Sonoma Raceway on Sunday as Power's nearest title contenders found trouble.
Helio Castroneves was penalized for running into the back of Scott Dixon on the first lap, Dixon broke his front wing running into Ryan Hunter-Reay, and Hunter-Reay was spun out late in the GoPro Indy Grand Prix by Alex Tagliani.
Power, who has lost the past two series titles to Dario Franchitti, heads to the season's final two races with a 36-point lead over Hunter-Reay.
The Andretti Autosport driver finished 18th after serving a penalty for running into the back of EJ Viso.
Hunter-Reay was visibly upset with Tagliani, and he marched down pit road to Tagliani's pit box to discuss the incident. Dixon was similarly irritated with Castroneves.
"That was a championship-deciding incident," Franchitti said of Dixon's spin. "(Dixon and Hunter-Reay) were innocent parties in that."
All the penalties came for contact in the reconfigured Turn 7.
Briscoe's win was his first in the series since the June race at Texas Motor Speedway in 2010. He now has seven career wins.
Franchitti finished third, with Rubens Barrichello an IndyCar-best fourth and Graham Rahal fifth.
Among the title contenders, Castroneves rallied to finish sixth. Dixon was 13th.
Castroneves was penalized for avoidable contact, dropping him from the fourth starting spot to 21st. Dixon kept the car running, but fell back through the field to 16th.
Dixon also suffered a broken front wing on Lap 45 when he ran into the back of Hunter-Reay in a battle for position. He tried to stay on the track as long as possible but had to come to pit road on Lap 58.
The big crash came on Lap 64. Sebastien Bourdais, the No. 3 qualifier, was in that position when he left pit road. But with cold tires, he got into a battle for track position with rookie Josef Newgarden.
Newgarden got under him heading to Turn 7, sending Bourdais wide, and it appeared debris got on Bourdais' tires. When he came to Turn 8, he had no control of the car and he veered to the right, through the dirt. The car wiggled, then spun into the path of Newgarden.
The contact pushed Newgarden into a barrier, a vicious hit for the Sarah Fisher Hartman Racing machine, which took a secondary hit from Bourdais' car. It was a mess.
Fortunately, Newgarden walked away from the accident, although he suffered a left index finger injury.
"It was my fault, obviously, because I steer the car," Bourdais said. "But the car refused to turn."
It was during that exchange that Power, who was on pit road at the time of the crash, lost the lead to Briscoe. Power dominated the race and should have been able to circle the track and be ahead of Briscoe as he pitted.
But Power had to slow up for the lapped cars of Charlie Kimball, Sebastian Saavedra and Justin Wilson, and Briscoe beat him off pit road.
"We got a timely yellow and then (Power's crew) made a little mistake in the pits," Briscoe said.
Power congratulated Brisoce, who does not have a contract for next season. Power just got unlucky that IndyCar left the pits open. It didn't help that his right rear tire changer was slow to release.
"Had I not gotten held up, I would have won the race," Power said. "I was ahead by eight seconds; we gave away four (seconds) with the tire. But not being able to get around those guys cost me dearly.
"I couldn't pass them under yellow."