Kurt Busch cruises in the Toyota/Save Mart 350 at Infineon Raceway

Before his opening practice laps for this year’s NASCAR Sprint Cup Series race in California wine country, Kurt Busch was asked to grade his Penske Racing team.

Busch assigned it a B-plus — a promising, if at times struggling, effort with no victories.

That changed Sunday when Busch and his team brought their “A” game with a dominant victory in the Toyota/Save Mart 350 at Infineon Raceway, which ended a winless streak at 38 races for the 2004 series champion.

Jeff Gordon finished second, Cup points leader Carl Edwards was third and Clint Bowyer finished fourth in front of about 93,000.

“It was one of those unbelievable days,” said Busch, who led 76 of the race’s 110 laps and earned the first road-course win of his career on the 10-turn, 1.99-mile Infineon track. “The car drove itself.”

“To get a road course win, it’s a big check mark on my list,” said Busch, 32, who has 23 career Cup victories.

For the cars behind Busch’s No. 22 Dodge, however, the racing was a lot more ragged. That was especially true for Tony Stewart and Brian Vickers, who wrote the latest chapter under NASCAR’s “Boys, have at it” doctrine of trying to let drivers settle disputes among themselves.

It started on Lap 37 when Stewart pushed Vickers from behind as they entered a sweeping right-hand turn, sending Vickers’ Toyota spinning and triggering a multi-car wreck that also collected Dale Earnhardt Jr., among others.

After getting repairs to his car, Vickers slammed into the back of Stewart’s Chevrolet entering the same turn 50 laps later, causing Stewart to spin and crash backward into the stacks of safety tires guarding the outside wall.

“I probably had it coming because I dumped [Vickers] earlier, but I dumped him because he was blocking,” said Stewart, a two-time Cup champion who had climbed as high as second behind Busch before his crash.

“I like Brian, I’m not holding it against him at all,” Stewart said. “If they want to block, that’s what is going to happen to them every time.”

Asked to give his side, Vickers said bluntly that Stewart “wrecked me and I wrecked him,” but that the hadn’t initially blocked Stewart as Stewart alleged.

Regardless, “I’m sure Tony and I will talk this week” and that “we’ll figure it out,” Vickers said. “It’s just racing.”

Vickers finished 36th in the 43-car field and Stewart was 39th.

Gordon, who holds the Infineon record with five Cup victories, declined to pass any judgment on the Stewart-Vickers payback but said that, generally speaking, picking a fight with the hard-nosed Stewart isn’t wise.

“He’s not a guy that you want to have gunning at you,” Gordon said. “He can get really mad.”

Busch first took the lead on Lap 13 and then seldom looked back, his car quickly jumping out to sizable leads in several restarts that followed caution periods.

“Once we got into the groove with this car, it seemed to get better after Lap 5 or 6,” Busch said. “Our cars have never done that before.”

Edwards leads the Cup standings by 25 points over Kevin Harvick, who finished ninth Sunday, and by 33 points over reigning champion Jimmie Johnson, who finished seventh.

The series continues at Daytona International Speedway with the Coke Zero 400 on Saturday.

james.peltz@latimes.com