Alberto Contador established an overall lead of nearly a minute in the Giro d'Italia after a solo stage win from Messina to Mount Etna.
Attacking seven kilometres from the ninth stage's finish for his first ever win of the Giro, Contador shook off Jose Rujano 1.5kms from the summit.
With the Venezuelan taking second, Italy's Stefano Garzelli was third, around 50 seconds back.
Contador's win gave him the leader's pink jersey from Pieter Weening.
"I've opened up some big differences," said triple Tour de France winner Contador, who rides for the Saxo Bank team. "My legs were going well and I had to attack."
"My only real concern was the strong wind, but I saw that Michele Scarponi was in trouble and I knew I had to keep trying," added Contador, who won the Giro in 2008.
"I've always wanted to win on a volcano and this was my opportunity, though there are a lot more chapters left in this year's Giro."
But Contador's rivals are already eyeing stages in the Dolomites and Alps as possible opportunities to peg back the Spaniard.
"We've seen how well he's going, but there will be chances to bounce back," said Italian Vincenzo Nibali, third in last year's Giro and currently fourth overall.
Nibali's compatriot Scarponi, who finished fourth in 2010, added: "He was the big favourite before the start, and he's taken a big step forward, but the race is far from over."
Contador is competing in the Giro after being cleared by the Spanish cycling federation over his positive test for banned substance clenbuterol in last year's Tour.
He is awaiting the outcome of an appeal against that decision by the International Cycling Union (UCI) and World Anti-Doping Agency (Wada) at the Court of Arbitration for Sport.
Meanwhile Wada has opened an independent investigation in an attempt to discover who leaked an internal document from the UCI which listed the 'doping risk' of each entrant in last year's Tour.
The list rated riders from 0 - not suspicious - to 10 - highly suspicious.
The report suggested that 156 riders showed "little or no risk" of doping, with 42 riders among the "suspect" categories.