Simon Yates claimed his first career Tour de France victory on stage 12 from Toulouse to Bagneres-de-Bigorre.
The Mitchelton-Scott rider held off Gregor Mulhberger and Pello Bilbao in a sprint after the trio got away from their fellow escapees on the climb of the Hourquette d'Ancizan with a little over 30km remaining of the 209.5km stage.
Yates, the 2018 Vuelta a Espana winner, is riding the Tour to help his twin brother Adam's general classification ambitions, but having lost over an hour in the overall during the first 10 stages he took his opportunity to go after some individual glory.
Simon Yates drove hard on the final section on the Hourquette, the second of two category one climbs on the Tour's second mountain stage.
Bora-Hansgrohe's Muhlberger was able to follow the Mitchelton-Scott man over the summit, with Astana's Bilbao not far behind, and the trio raced down the long descent into town together.
Simon Yates looked the least likely of the three to win in a sprint given his slight frame but he used some of his former track racing nous to attack on the way into a corner with 200 metres to go, before getting the power down on the final straight.
News of Simon's win brought a broad smile to the face of Adam as the peloton arrived into the town almost 10 minutes later.
Frenchman Julian Alaphilippe of Deceuninck-Quick Step managed to remain with the main contenders over the Peyresourde and the Hourquette to retain the yellow jersey for another day.
Defending champion Geraint Thomas, second in the general classification, will hope to take a chunk out of his 72-second deficit in Friday's 27km time trial in Pau.
Nicolas Roche (Team Sunweb), who finished sixth in stage nine last Sunday, crossed in 15th and is 27th in the general classification. His cousin Dan Martin meanwhile stays in the top ten. He's ninth overall for UAE Team Emirates.