Eli Tomac of Cortez crashed early in the 450 Supercross in San Diego but recovered to race from 20th place to a ninth-place finish.
Few racers escaped the carnage at the start of the race.
As the gate dropped, Justin Cooper, Ken Roczen and Aaron Plessinger went to the lead. Jett Lawrence crashed in the first lap and fell to the back of the pack. Chase Sexton and Malcolm Stewart also went down and landed in the bottom five.
Tomac crashed with Christian Craig, and Cooper also crashed in the second lap as Roczen, Jason Anderson and Plessinger ran in front.
Plessinger overtook Anderson for second in Lap 4 and inherited the lead in Lap 8 when Roczen crashed.
Meanwhile, Tomac had climbed from 20th place to 13th. However, he joined the lapped riders in the 12th lap, racing in 10th place. Ten laps later, he finished ninth, behind Sexton.
Following the race, Tomac issued a statement via his team at Star Racing Yamaha.
"It was a tough weekend. I got tangled up with (Christian) Craig down a rhythm section, and that set me way back early in the race. I had a decent recovery, though, and I look forward to racing on a dry surface sooner rather than later,” Tomac said.
Tomac entered Snapdragon Stadium in third place in the standings after finishing second to Sexton last week in San Francisco. Now, after three races in the 17-race Monster Energy AMA Supercross Championship series, Tomac sits in seventh place overall.
With the win in San Diego, Plessinger took over the standings lead. Sexton remained in second after finishing behind Plessinger, and Jett Lawrence was third. Anderson of Rio Rancho, New Mexico, is in fourth, and Cooper Webb is in fifth.
For Tomac, the main event was a rough end to a smooth day of qualifying rounds.
He was second-fastest during timed practice rounds, with a best lap of 52.223 seconds, behind Roczen, at 52.027 seconds.
And he won his qualifying heat after overtaking Jett Lawrence in the third of seven laps and riding to a victory over Stewart and Jett Lawrence.
Plessinger won Heat 2 after overtaking Roczen, who finished second ahead of Sexton.
Next Saturday, the series returns to Angel Stadium for the second time this season, Anaheim 2.
| Rider | Team | Points |
| 1. Aaron Plessinger | KTM | 60 |
| 2. Chase Sexton | KTM | 59 |
| 3. Jett Lawrence | Honda | 56 |
| 4. Jason Anderson | Kawasaki | 49 |
| 5. Cooper Webb | Yamaha | 49 |
| 6. Dylan Ferrandis | Honda | 49 |
| 7. Eli Tomac | Yamaha | 48 |
| 8. Ken Roczen | Suzuki | 42 |
| 9. Justin Barcia | GasGas | 40 |
| 10. Jorge Prado | GasGas | 35 |
