Il tracciato di San Diego, realizzato da Ricky Johnson, ha presentato delle interessanti novità rispetto ai tracciati visti fin´ora: la curve erano tutte ad ampio raggio, più veloci e scorrevoli, con diverse traiettorie.
Al via della 250 Ryan Dungey guida la gara seguito da Morais e Reardon, Weimer è sesto. Dopo metà gara Weimer recupera fino alla terza posizione e la gara si chide con Dungey vincitore che torna al comando della classifica,
The track, as mentioned, designed by Rick Johnson, had some nice changes on it – a lot of the corners were more ´wide open´ instead of being tight corners. Rick´s input had some of the track´s corners more sweeping and off camber, rather than tight 90 degree or 180 degree corners.
Al via della 450 Mike Alessi parte al comando ma bastano pochi metri a Stewart per prendere il comando con Chad Reed al suo inseguimento. Una caduta alla prima curva coinvolge Tim Ferry. I primi due scappano con Reed a due secondi dal leader. Stewart vince anche a San Diego e si porta in testa alla classifica generale.
Classifica 450
| 1 | 7 | James M. Stewart | Haines City, FL | Yamaha YZ450F | 20 | — | |
| 2 | 1 | Chad Reed | Tampa, FL | Suzuki RM-Z450 | 20 | 8.252 | |
| 3 | 29 | Andrew T. Short | Smithville, TX | Honda CRF450R | 20 | 9.784 | |
| 4 | 2 | Ryan D. Villopoto | Seattle, WA | Kawasaki KX450F | 20 | 9.971 | |
| 5 | 18 | David D. Millsaps | Carlsbad, CA | Honda CRF450R | 20 | 22.744 | |
| 6 | 800 | Mike A. Alessi | Victorville, CA | Suzuki RM-Z450 | 20 | 25.305 | |
| 7 | 14 | Kevin W. Windham | Centreville, MS | Honda CRF450R | 20 | 28.299 | |
| 8 | 26 | Michael Byrne | Newnan, GA | Suzuki RM-Z450 | 20 | 36.11 | |
| 9 | 27 | Nicholas A. Wey | Murrieta, CA | Yamaha YZ450F | 20 | 36.457 | |
| 10 | 9 | Ivan Tedesco | Tallahassee, FL | Honda CRF450R | 20 | 37.376 | |
| 11 | 28 | Charles J. Summey | Huntersville, NC | KTM 450SX-F | 20 | 50.638 | |
| 12 | 48 | Thomas K. Hahn | Decatur, TX | Kawasaki KX450F | 19 | — | |
| 13 | 38 | Kyle P. Chisholm | Valrico, FL | Yamaha YZ450F | 19 | — | |
| 14 | 15 | Timmy M. Ferry | Largo, FL | Kawasaki KX450F | 19 | — | |
| 15 | 13 | Heath D. Voss | Mico, TX | Honda CRF450R | 19 | — | |
| 16 | 59 | Troy K. Adams | Homosassa, FL | Honda CRF450R | 19 | — | |
| 17 | 141 | Steve Boniface | Corona, CA | Honda CRF450R | 18 | — | |
| 18 | 979 | Ben Coisy | Murrieta, CA | Honda CRF450R | 16 | — | |
| 19 | 60 | Broc D. Hepler | Kittanning, PA | Yamaha YZ450F | 15 | — | |
| 20 | 33 | Joshua M. Grant | Riverside, CA | Yamaha YZ450F | 7 | — |
Classifica 250
| 1 | 10 | Ryan M. Dungey | Belle Plaine, MN | Suzuki RM-Z250 | 15 | — | |
| 2 | 116 | Ryan Morais | Murrieta, CA | Kawasaki KX250F | 15 | 4.075 | |
| 3 | 19 | Jake T. Weimer | Rupert, ID | Kawasaki KX250F | 15 | 4.942 | |
| 4 | 39 | Trey G. Canard | Shawnee, OK | Honda CRF250R | 15 | 14.998 | |
| 5 | 31 | Ryan Sipes | Vine Grove, KY | KTM 250SX-F | 15 | 22.957 | |
| 6 | 114 | Justin D. Brayton | Murrieta, CA | KTM 250SX-F | 15 | 24.775 | |
| 7 | 63 | Chris Blose | Phoenix, AZ | Honda CRF250R | 15 | 27.104 | |
| 8 | 42 | Jake Moss | Temecula, CA | Honda CRF250R | 15 | 37.717 | |
| 9 | 801 | Jeff Alessi | Victorville, CA | Honda CRF250R | 15 | 41.852 | |
| 10 | 220 | Cole Seely | Newbury Park, CA | Suzuki RM-Z250 | 15 | 46.166 | |
| 11 | 410 | Eric J. McCrummen | Oakley, CA | Honda CRF250R | 15 | 54.29 | |
| 12 | 350 | Ben D. Evans | Boise, ID | Honda CRF250R | 14 | — | |
| 13 | 85 | Sean D. Borkenhagen | Huntington Beach, CA | Honda CRF250R | 14 | — | |
| 14 | 186 | Derek J. Costella | Las Vegas, NV | Honda CRF250R | 14 | — | |
| 15 | 144 | Alex J. Martin | Millville, MN | Honda CRF250R | 14 | — | |
| 16 | 138 | Michael J. Lapaglia | Murrieta, CA | Suzuki RM-Z250 | 14 | — | |
| 17 | 55 | Ryan D. Clark | Waddell, AZ | Honda CRF250R | 14 | — | |
| 18 | 122 | Dan Reardon | Menifee, CA | Honda CRF250R | 14 | — | |
| 19 | 931 | Danny R. Bajza | Menifee, CA | Honda CRF250R | 14 | — | |
| 20 | 111 | Michael J. Sleeter | Temecula, CA | KTM 250SX-F | 14 | — |
