The 450 main opened with a flurish as heat winner Roczen took the holeshot but it was Tomac who quickly took control as Roczen, and Musquin squared off as Savatgy paid the duo some close attention. Savatgy, Baggett, Webb, Seely and Hill all filled the top ten.
For four laps Tomac, Roczen and Musquin were all within a bike length before Roczen made his move into the lead on lap five. The duo went wheel to wheel until Tomac tucked the front end and crashed, dropping down to seventh. This left a trio of KTM's in Musquin, Baggett and Webb to fill out the next three spots behind Roczen. With nine minutes to go Webb demoted Baggett to claim third and set out after team-mate Musquin. In the closing minutes, it was Webb who was laying down the fastest laps and putting loads of pressure on Musquin as both drew closer to Roczen. With three laps to go Webb got by his team-mate and set out after Roczen.
The final three laps were a nail biter as Webb laid down some serious pressure on Roczen, but the German never faltered. It took a no holds barred move on the final corner for the KTM rider to grab the advantage and take the win by an incredible 0.028 of a second. The win sees Webb log his fourth win of the season and take back the championship leaders Red Plate. Musquin and Baggett took third and fourth while Savatgy held of Cole Seely for sixth