The list of unexpected winners of the Toyota/Save Mart 350 seems to grow with each passing year. Maybe that alone gives Brad Keselowski reason to feel optimistic about his chances in Sunday's NASCAR Sprint Cup race at Sonoma Raceway.

Keselowski, in his fifth season at Penske Racing, freely admits that "Sonoma's probably my weakest track on the circuit." But drivers such as Kasey Kahne and Martin Truex Jr. also had experienced limited success on road courses before each won at Sonoma in recent seasons.

Keselowski has never finished higher than 10th in four starts at Sonoma, but considering how consistent his team has been through the first 15 races of this season, perhaps this could be a breakthrough year.

"I think we have an opportunity to go there and not only perform well, but hopefully win," Keselowski said in a phone interview last week. "That's what you hope for as a driver every week, but especially at a track that's one of your weakest. It would mean a lot to me to win there."

Keselowski, who has 11 career Cup victories and 40 top-5 finishes, seemed to be in position for another top-10 result at Sonoma last season, even leading the race for seven laps. But he was involved in an accident on a late restart and wound up 21st. Truex went on to capture his first victory on a road course.

It was all part of a disappointing 2013 for Keselowski, who finished 14th in the standings a year after winning the season championship.

This season, Keselowski has regained some of the form that he showed in 2012, with seven top 10s in 15 races. He's finished in the top three the last three weeks, coming in second to Jimmie Johnson at Dover on June 1 and to Dale Earnhardt Jr. on June 8 at Pocono, and was third at his hometown track of Michigan on Sunday.

Keselowski's race at Pocono could have easily resulted in his second victory of the season.

He led the race in the late stages but had debris on his grille, and his engine began to overheat. He tried to get behind Danica Patrick's car to remove the trash, hoping the air flow between the two cars would make it fly away, but the move backfired. Earnhardt passed Keselowski, led the final five laps and took the checkered flag.

"It's never fun losing a race that you feel like you were supposed to win, but racing has a way of doing that to you," Keselowski said. "There are probably races that I've won where I've beaten others that were in similar standing. It can be frustrating, but you just have to sit back and acknowledge that it kind of goes both ways. You just hope that more often than not that it goes your way."

Keselowski said after the race in Michigan that Hendrick Motorsports has an advantage right now with its engines, and it's hard to argue considering Jeff Gordon, Johnson and Earnhardt take up the top three spots in the Cup standings. Hendrick drivers have won five straight races, including three by Johnson.

"I just know our cars are fast," Johnson said after winning in Michigan. "They run good. The cars are all pretty equal aero-wise with what the rules are from NASCAR."

Still, Keselowski is optimistic about the rest of the summer, starting with this week.

"As a race car driver, you'd like to win every race, but that's also not realistic," he said. "I'm happy with where we're at."

Follow Curtis Pashelka on Twitter at twitter.com/CurtisPashelka.

WEEKEND SCHEDULE

At Sonoma Raceway
Saturday's qualifying: NASCAR Sprint Cup series qualifying, 10:30 a.m., Fox Sports 1
Sunday's Sprint Cup race: Toyota/Save Mart 350, noon, TNT

sprint cup leaders

Driver Pts Wins
Jeff Gordon 537 1
Jimmie Johnson 522 3
Dale Earnhardt Jr. 514 2
Matt Kenseth 513 0
Brad Keselowski 490 1