New Zealand's Scott Dixon will try to hold off Brazilian Helio Castroneves for the IndyCar crown as the US open-wheel racing series concludes Saturday.

Dixon goes into the season finale with a 25-point lead atop the standings, having seized the lead from Castroneves with a win and a runner-up finish at the double-header in Houston two weeks ago.

If Dixon finishes fifth or better on the oval course in Fontana, east of Los Angeles, he will seal his third IndyCar crown regardless of where Castroneves finishes.

"I think for us the easiest way to approach it is how we typically approach a race weekend, and that's to go there setting our sights on winning it," said Dixon, who won the series title in 2003 and 2008.

But Castroneves's Team Penske made it clear in Friday's qualifying they're ready to take the battle to the very end, notching the three fastest qualifying times.

Castroneves, a three-time Indianapolis 500 winner, had taken the provisional pole with a two-lap average speed of 219.677 mph (353.54 Km/h), when teammate Will Power of Australia recorded a two-lap average of 220.775 mph (355.3 Km/h) to claim his third pole of the season.

Power said that he wasn't trying to do his championship-chasing teammate out of the fastest time, but was trying to make sure that Dixon wouldn't deliver an even quicker performance and claim the bonus point that goes to the fastest qualifier.

In any event, both Dixon and Castroneves will start in the middle of the pack when it comes to race day, both incurring a 10-grid spot penalty for unapproved engine changes.

Dixon said the advantages of changing the engine between qualifying and the race outweighed the penalty.

"For us, it was more paramount to change the engine and make sure we took the performance gain," he said.