Former champion Ryan Dungey won the supercross race Saturday night in the season's third and final event at Angel Stadium, his first victory of the season.
Cole Seely finished second in the 20-lap main event and Eli Tomac was third.
Ken Roczen, who had won the two previous races in Anaheim this year, finished fourth. Trey Canard, last week's winner in Oakland, was fifth.
Dungey, a 25-year-old Minnesotan, had arrived in Anaheim atop the season points standings after scoring four top-five finishes in the previous four races, including runner-up finishes in the last two.
The victory stretched his lead to 11 points over the second-place Roczen.
Despite the top-five consistency that had carried him to the top of the standings, Dungey, who rides for KTM, hadn't won a race before Saturday.
Supercross is the stadium version of motocross, or off-road motorcycle racing.
Dungey earned his championship in 2010, the last title won by anyone other than Ryan Villopoto, who reeled off four in a row from 2011 to 2014.
But Villopoto opted to race overseas this year, so supercross will crown a different champion for the first time since Dungey won the title.
Another former champion, 32-year-old Chad Reed, is off to a lackluster start this season — he was 10th in the title standings entering Saturday's race — and the Australian finished sixth Saturday night.
In the sport's second-level 250SX series, Cooper Webb won the 15-lap main event and Jessy Nelson finished second in a race that had to be restarted.
In the first attempt, Webb had just taken the lead on his Yamaha when the race was halted on Lap 6 because officials ruled the starting gate malfunctioned, denying the riders an even start.
Webb, of Newport, N.C., passed Nelson for the lead on the ninth lap of the restarted race and won by 3.7 seconds.