While the GC fight warmed up behind him, the day belonged to Teuns whose last victory came at the Arctic Race of Norway in August 2017.
“I’ve had to wait for almost two years to finally get a victory," he said. "It’s also a very nice one. It makes me very happy.
"From the start, it was a crazy stage with a big breakaway. It was full gas all the way. The peloton had to chase on a very hard pace. When the last breakaway riders got pulled back, I saw many guys were tired and I felt there was a possibility to do something and take my opportunity.
"In the last steep climb, I made a difference with Guillaume Martin who was a very good companion until the finish. He was the strongest uphill. I’m glad I could finish it off in a man-to-man sprint after he surprised me in the last corner. I had to go full gas to go over him. It’s a dream come true for me to be the leader of such a nice race like the Dauphiné.”
Astana's Jakob Fuglsang sits four seconds ahead of the group of favourites he finished with including Chris Froome (INEOS), Thibaut Pinot (Groupama-FDJ), Michael Woods (EF Education First) and Nairo Quintana (Movistar), the Dane bagging valuable bonus seconds after crossing the line third.
Australian Richie Porte lost 31 seconds to his main rivals. The Trek-Segafredo rider finished in a group with local hope Romain Bardet (AG2R La Mondiale) - both dropped on the final climb.
Sunweb's Tom Dumoulin showed signs he's probably here purely to test his knee and get some race days in before the Tour de France as opposed to slogging it out for the overall victory. He finished the day eight minutes and 50 seconds behind Teuns and just over nine minutes in GC arrears.
The 177km third stage heads north and includes four testing climbs on the route through central France from Le Puy-en-Velay to the town of Riom outside Clermont-Ferrand.