Watch: Arlington 3 SX Highlights
Video courtesy of NBC Motorsports
In the 250SX class, Justin Cooper put together the first perfect night of his career. He’s topped every qualifying session so far this season (including the untimed practices as well), but then he holeshot and won his heat race, and then holeshot, led every lap, and won the main event to earn his third career main event win and reclaim the points lead. After round five of the 250SX West Region, Cooper has a two-point lead over Cameron McAdoo, who finished second on the night. Rookie Seth Hammaker earned his second career podium with a third-place finish.
| Rider | Time | Interval | Best Lap | Hometown | Bike | |
|---|---|---|---|---|---|---|
| 1 |  Justin Cooper | 19 Laps | 0:50.179 | Cold Spring Harbor, NY  | Yamaha YZ250F | |
| 2 |  Cameron McAdoo | +03.538 | 0:50.212 | Sioux City, IA | Kawasaki KX250 | |
| 3 |  Seth Hammaker | +11.016 | 0:50.482 | Bainbridge, PA | Kawasaki KX250 | |
| 4 |  Jalek Swoll | +17.390 | 0:50.581 | Belleview, FL | Husqvarna FC 250 | |
| 5 |  Hunter Lawrence | +22.891 | 0:50.133 | Landsborough, Australia  | Honda CRF250R | |
| 6 |  Garrett Marchbanks | +26.258 | 0:50.646 | Coalville, UT | Yamaha YZ250F | |
| 7 |  Chris Blose | +32.154 | 0:52.100 | Phoenix, AZ | GasGas MC 250F | |
| 8 |  Kyle Peters | +34.700 | 0:51.841 | Greensboro, NC | Honda CRF250R | |
| 9 |  Nate Thrasher | +36.679 | 0:51.132 | Livingston, TN | Yamaha YZ250F | |
| 10 |  Jarrett Frye | 18 Laps | 0:52.751 | Mechanicsville, MD | Yamaha YZ250F |
The 450SX class once again saw the riders 1-2-3 in the championship standings start in the top three for the second main event in a row. This time, they were joined by Justin Barcia (fourth in the standings) at the front, who eventually battled with Tomac for the final spot on the podium. Out front, Ken Roczen led the first 19 laps before Cooper Webb pulled off a pass in the whoops to take over the lead. Webb was able to holdoff Roczen to claim his sixth win of the season—the 17th of his 450SX career. With the win, Webb holds a 15-point lead over Roczen after 12 rounds. After a mistake that cost him third place to Barcia, Tomac was able to retake the position and claim his sixth podium finish of the season.
Arlington 3 (West) - 450SX Main Event
March 21, 2021| Rider | Time | Interval | Best Lap | Hometown | Bike | |
|---|---|---|---|---|---|---|
| 1 |  Cooper Webb | 26 Laps | 0:48.757 | Newport, NC | KTM 450 SX-F | |
| 2 |  Ken Roczen | +01.351 | 0:48.749 | Mattstedt, Germany  | Honda CRF450R | |
| 3 |  Eli Tomac | +03.434 | 0:48.576 | Cortez, CO | Kawasaki KX450 | |
| 4 |  Justin Barcia | +05.586 | 0:48.794 | Monroe, NY | GasGas MC 450F | |
| 5 |  Jason Anderson | +15.282 | 0:49.152 | Edgewood, NM | Husqvarna FC 450 | |
| 6 |  Malcolm Stewart | +30.449 | 0:49.672 | Haines City, FL | Yamaha YZ450F | |
| 7 |  Dylan Ferrandis | +31.399 | 0:49.588 | Avignon, France  | Yamaha YZ450F | |
| 8 |  Joey Savatgy | +33.465 | 0:49.786 | Thomasville, GA | KTM 450 SX-F | |
| 9 |  Aaron Plessinger | +36.393 | 0:49.839 | Hamilton, OH | Yamaha YZ450F | |
| 10 |  Dean Wilson | 25 Laps | 0:50.333 | Scotland, United Kingdom  | Husqvarna FC 450 |
