Motorsport: Dixon second in Sonoma

Australian Will Power has extended his Indycar Championship lead with a victory in Sunday's Sonoma grand prix in California, followed home by New Zealander Scott Dixon.

The Queenslander led from the start of the 75-lap race at Infineon speedway, barely being challenged as he cruised to his fifth race win of the season.

The victory also erases some personal demons for Power, who left Infineon last year in the back of a medical helicopter after fracturing several vertebrae in a serious crash during a practice session.

Dixon finished second, with Power's main rival Dario Franchitti coming in third.

Power now has a 59-point lead in the championship with four races remaining.

Power's Australian teammate, Ryan Briscoe, finished fourth.

The next race is the Indy 300 at the Chicagoland Speedway in Joliet, Illinois on August 28.

- AAP