Scott Dixon clocked the fastest lap in practice on Friday for the IndyCar GoPro Grand Prix of Sonoma on the road course in Sonoma, Calif.
Dixon covered the 2.385-mile, 12-turn circuit in 1 minute, 18.3145 seconds during the 45-minute afternoon session. Right behind him was season points leader Helio Castroneves, .3549 of a second slower. Dixon trails Castroneves by 31 points in the season standings.
"Year after year, the championship comes down to the last race and we'll just carry on and try to get the most points out of each race," said Dixon, a two-time series champion.
Ryan Hunter-Reay is third in the season standings and also was third in practice, turning a lap of 1:18.6814. Will Power and Dario Franchitti rounded out the top five in practice.
Three rounds of qualifying are set for Saturday, followed by the 85-lap race on Sunday.
"It's wide open; anything can happen," Castroneves said of the points chase.
Power holds the track qualifying record of 1:17.2709 set last year.