Esteban Chaves and Simon Yates made it a Mitchelton-Scott one-two as they crossed the finish line together on the sixth stage of the Giro d'Italia.
Yates's second place on the stage was good enough for him to take the race leader's Maglia Rosa (pink jersey) off BMC's Rohan Dennis -- who struggled on the first mountain-top finish of this year's race.
"It's unbelievable. This is the best start for the Giro d'Italia," said Chaves on the finish line.
"I made the break with Jack (Haig), I want to say thank you for Jack, he pulled a lot in the breakaway. In the final I rode with Yates, I was first and he claimed the Maglia Rosa. How unbelievable is that? I think also I'm in the king of the mountains jersey -- it's like a dream. Now we go to the mainland -- we're super excited and will keep on dreaming."
Thursday was the first true test for the general classification favourites, finishing as it did on Mount Etna. In total, the riders covered 164km from Caltanissetta to Etna, with the finishing climb totalling 15km at a 6.5% average gradient.
The first 50km of racing saw many attacks, including Natnael Berhane for Team Dimension Data for Qhubeka. The peloton remained ever-watchful of those early breaks but eventually allowed a group of 28 riders to go clear, including Jacques Janse van Rensburg for Africa's Team.
Rohan Dennis' BMC and the Astana team led the peloton as they made sure to keep the time-gap in check and this resulted in the remnants of the breakaway only holding a one minute lead at the foot of Mount Etna.
Once, the road headed uphill the fireworks started.
Louis Meintjes, Team Dimension Data for Qhubeka's erstwhile on-road leader, was one of the first GC contenders to lose contact and the South African never latched back on. Africa's Team though did have Ben O'Connor still with the GC group and the Australian rode strongly to only lose contact when the final attacks started with 2km to go.
By that stage Colombian Chaves had broken clear and looked to have the stage win sealed. That was until Yates showed good legs to ride away from the reduced peloton and catch his teammate in the final 500m.
The two rode in sync to the line where Chaves was given right of passage to take the stage win by the Briton. Some 26 seconds later Thibaut Pinot (Groupama-FDJ) crossed the line to round off the podium and then it was a case of seeing how much damage to GC hopes the climb up Mount Etna made.
Dennis was the biggest loser after finishing 1:04 down, but defending champion Tom Dumoulin, Chris Froome and local favourite Fabio Aru finished together (in Pinot's slipstream) in their own battle of wits and strength.
"I wasn't super today but I was there so it was alright. It was good that with not the best legs I could still hang on," said Dumoulin in his post-stage media responsibilities.
"I still have a good position int he GC but today I wasn't the best. It was a difficult final climb, really long and challenging. It's difficult to draw conclusions based on today."
O'Connor finished 12th, 43 seconds behind Chaves and he is now Team Dimension Data for Qhubeka's best-placed rider in 13th overall and second in the young rider competition. Meintjes, meanwhile, has dropped down to 26th overall after a tough day in the saddle.
"With about 2.5km to go I was detached, but kept my cool and tried to limit the loss still hoping to maybe grab the white jersey," said O'Connor post-race.
"I just missed it sadly, but it's certainly within reach later in the week and really I'm so pleased to be up there with the best again on one of the most iconic climbs around and in the Giro d'Italia!