Bonneville - Astana's Danish rider Jakob Fuglsang outshone defending champion Chris Froome and Australian Richie Porte to win the final stage of the Criterium du Dauphine and claim overall victory on Sunday.
Fuglsang, a silver medallist in the road race event at last year's Rio Olympics, went into the stage in third place.
But he managed to overhaul his rivals on a gruelling mountain ride, 115km long over three cols (Saisies, Aravis, Colombiere) before a final climb to the finish line at the Plateau de Solaison, high in the Alps.
The 32-year-old Dane soloed to the stage win, finishing 12 seconds ahead of Ireland's Dan Martin. Crucially, overnight leader Porte was 1:15 off the pace and Froome, who started the ride in second, a further 21 seconds adrift.
Fuglsang's victory meant he leapfrogged Porte in the overall standings, the Australian claiming second at 10 seconds with Martin rounding out the podium by 1 second from Froome, the three-time Tour de France winner.
"It's amazing! I don't know what to say. Even with the jersey I can't believe it, I've been close to the yellow jersey many times in my career," Fuglsang said, dedicating the win to his pregnant wife.
"We tried to keep our positions on GC and it came down to a big big fight for the overall victory.
"We planned it very well with Fabio (Aru) attacking (with Alejandro Valverde on the Col de la Colombiere) and everything went in our favour.
"We played really smart. Froome had to pull after Fabio and 'Valv'. I tried to keep cool all day, and without pushing too much I went for the stage win and I got it all."
The Dane said the victory was a warning shot at rival teams for the July 1-23 Tour de France.
"There's still a long way to the Tour but I'm really happy with my condition now. I'll have to take it easy onto the Tour," he said.
"With Fabio we'll form a good couple for the Tour. We'll share the leadership and we have a good team."
Team Sky sporting director Nicolas Portal insisted Froome would have more to offer come the Tour de France after a tough week's racing.
"It's a different Dauphine from the last number of years," Portal said.
"We came here to try to win, and we saw Richie was super strong, and now we can see Fuglsang was clearly very strong too.
"These two riders were slightly better than us but the team rode fantastic every day."
Portal added: "Froomey is on the way up, step by step to the Tour. For sure he's going to progress. He finished the race really well here, making some hard attacks and some long pulls.
"Obviously it didn't work out with the victory, but we've done a really good job here. We're all looking forward to the Tour and there's more to come."
Results and standings after the eight and final stage of the Criterium du Dauphine on Sunday, a 115km ride from Albertville to the Plateau de Solaison:
1. Jakob Fuglsang (DEN/AST) 3hr 26min 20sec, 2. Dan Martin (IRL/QST) at 12sec, 3. Louis Meintjes (RSA/EAU) 27, 4. Emanuel Buchmann (GER/BOR) 44, 5. Fabio Aru (ITA/AST) 1:01, 6. Romain Bardet (FRA/ALM) 1:02, 7. Richie Porte (AUS/BMC) 1:15, 8. Chris Froome (GBR/SKY) 1:36, 9. Rafael Valls (ESP/LOT) 1:41, 10. Alejandro Valverde (ESP/MOV) 3:30
11. Alberto Contador (ESP/TRE) 4:10
1. Jakob Fuglsang (DEN/Astana) 29hr 05min 44sec, 2. Richie Porte (AUS/BMC) at 10sec, 3. Dan Martin (IRL/QST) 1:32, 4. Chris Froome (GBR/SKY) 1:33, 5. Fabio Aru (ITA/AST) 1:37, 6. Romain Bardet (FRA/ALM) 2:04, 7. Emanuel Buchmann (GER/BOR) 2:32, 8. Louis Meintjes (RSA/EAU) 3:12, 9. Alejandro Valverde (ESP/MOV) 4:08, 10. Rafael Valls (ESP/LOT) 4:40
11. Alberto Contador (ESP/TRE) 5:20