Simon Yates became only the fourth Briton to wear the Giro d'Italia's pink jersey after finishing second on stage six behind his Michelton-Scott team-mate Esteban Chavez.
Yates, who moved to the top of the standings after breaking away from the peloton late in the stage, follows Mark Cavendish, Sir Bradley Wiggins and David Millar in leading the prestigious race.
Chaves held a long-time lead on Mount Etna before being caught late on by Yates, who nevertheless allowed the Colombian to cross the line first as the stage winner.
"I said to him as soon as I caught him that he could take the stage because if I had enough time I would take the jersey," Yates said. "He'd been up the road all day and he deserved it."
Yates had started the day in third place, 17 seconds behind overall leader Rohan Dennis, but he now goes into stage seven with a 16-second advantage over Team Sunweb's Tom Doumoulin, with Chaves moving up up to third.
Yates added: "It was a crazy day with lots of attacks going at the beginning. As Esteban was at the front with a pretty big group, it made me sit back.
"It worked out perfectly. I felt good so I took my chance to ride across. I knew I was taking the Maglia Rosa, which pleases me a lot."
Chris Froome moved up to eighth place in the overall standings, one minute and 10 seconds behind Yates, after finishing in 10th place in the chasing group.