The Canadian crossed the line ahead of Colin Joyce (Axeon Hagens Berman) and BMC's Rick Zabel.
"I was back a little bit, so I pretty much went from 1km. I went up the side and then punched it with like 300 or 400 metres to go. It was early. It was a long sprint, but somehow nobody came around me and I kept going. That was that." Dahl told Cycling News.
The attacks came immediately once the bunch was out of the neutral zone. The day's break gained an advantage of five minutes before BMC applied the pressure reigning in the final stragglers before the final lap of the Cedar City circuit.