Considered one of the toughest stages of the race, today's 147 mile-long tester from Gravellona Toce to Cervinia consisted of three major climbs and a mountain-top finish, and was seen as a penultimate chance for anyone to lay down a serious challenge to Contador for the overall title.

That did not happen today, but in breaking clear with six kilometres remaining, Aru moved back into second place, 4min 37 secs behind Contador, overhauling his Astana team mate Mikel Landa in the process.

Canada's 2012 Giro champion Ryder Hesjedal of Cannondale-Garmin finished second, 28 seconds behind Aru, while Quick-Step's Rigoberto Uran, the Colombian who finished runner-up in the last two editions of the Grand Tour, crossed the line third, 1:10 behind the leader.

Both Contador and Landa were in a group of riders who came in a further eight seconds behind, with Tinkoff-Saxo's Contador making clear afterwards how he was content to have matched his fellow Spaniard, his closest rival at the start of the day.

"I was marking Landa, my biggest rival," Contador said.

"Aru was the strongest today."

"I've been working for the pink jersey for five months.

"Winning a stage is secondary."

While the final stage on Sunday (May 31) is expected to be a procession, tomorrow's 124-miles leg from Saint-Vincent to Sestriere will be another gruelling one, providing the Astana riders with a last chance to break Contador.

The Spaniard is hoping become the first rider since Marco Pantani in 1998 to win the Giro and Tour de France in the same year.

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