Alberto Contador in pink after Jan Polanc wins in Abetone

In only his second Giro, 23-year-old Polanc left his mark after attacking from a five-man break on the second of two categorised climbs inside the final 10km of the stage.

Frenchman Sylvain Chavanel (IAM Cycling) held on for second place by half a bike length on Italy's Fabio Aru (Astana), who stole four precious bonus seconds for third place ahead of general classification rivals Alberto Contador (Tinkoff-Saxo) and Richie Porte (Team Sky).

The three main favourites for the 98th edition of the Giro fought hammer and tong on the final climb of the 152km stage in the race’s first mountaintop showdown – but nothing, besides those bonus seconds, could separate them after another frenetic day in the saddle.

Spaniard Contador now leads the race by just two seconds over Aru, with Australia’s Porte poised in third place a further 18 seconds back.

“I didn’t plan to attack,” Contador told Eurosport after receiving his pink jersey on the podium. “I looked at the other riders and I felt good. Aru and Richie are very strong but I think it’s a good situation after five stages. I’m happy – and hopefully I will still be in the lead come Milan.”

EARLY BREAK: The young Slovenian was part of a five-man break that formed around 10km after the start in La Spezia. Alongside veteran Chavanel the move featured Frenchman Axel Domont (Ag2R-La Mondiale), Switzerland’s Silvan Dillier (BMC) and Russia’s Serghei Tvetcov (Androni Sidermec).

The break held a gap of nine minutes over the peloton after they crested the summit of the Cat.3 climb to Foce Carpinelli, with one rider – Italy’s Alessandro Malaguti (Nippo-Vini Fantini) – stuck in no-man’s land while trying to bridge the gap.

With the advantage stretching out to over 10 minutes, Malaguti finally called it a day and sat up shortly after the feed zone in Castelnuovo di Garfagnana with around 70km remaining.

Once the riders passed through the town of Bagni di Luca the road headed uphill on a false flat ahead of the final 17km slog to the summit. With Orica-GreenEdge controlling the tempo in the interests of overnight maglia rosa Simon Clarke, the gap had been whittled down to six minutes as the leaders hit the final Cat.2 ascent.

POLANC DELIGHT: After individual attacks by Chavanel, Dillier and Domont, Polanc finally made the move that counted, edging clear of his fellow escapees with 10km remaining.

By now Tvetcov was long gone as Chavanel did his best to reel in the lone leader with a series of unseated digs in the big ring.

But all the action was happening further down the road as the Astana and Tinkoff-Saxo teams of Aru and Contador jostled on the front of the rapidly thinning pack – by now deprived of the pink jersey Clarke.

Astana sent both Tanel Kangert and Mikel Landa up the road in between dual attacks by Italian livewire Stefano Pirazzi (Bardiani-CSF). They came to nothing.

Contador then lit the torch paper with a surge 4.5km from the finish. Aru and Porte were able to respond – but once again Colombian Rigoberto Uran (Etixx-QuickStep) was found wanting. Uran would finish the stage 28 seconds behind the ‘Big Three’ and drops further down the standings.

Another Colombian, Esteban Chaves, saw his hopes of swapping the white youth jersey for pink fade after he struggled to keep up with the pace. Chaves was bidding to become the fourth Orica-GreenEdge - and the first non-Australian - to wear the maglia rosa since his team's opening day time trial win in San Remo.

Up ahead, Polanc danced on the pedals as he emerged from the Abetone forest and entered the closing straight. His lead had been cut considerably, but the win was his. Mouth agape and arms aloft, the Lampre-Merida tyro crossed the line after 4hrs 09mins 18secs in the saddle.

Polanc’s victory was the latest in a string of successes for cycling’s new generation after previous wins for Team Sky’s Elia Viviani (26), Orica-GreenEdge’s Michael Matthews (24) and Cannondale-Garmin’s Davide Formolo (22).

“I’d like to thank my team – for giving me the chance to ride in this Giro – my supporters, and of course my family and friends,” said an ecstatic Polanc.

ARU INTENT: Porte was the next of the favourites to test his legs after Contador had been reeled in. But it was Aru – bolstered by the return of team-mate Landa – who had the last say after a stinging attack inside the last kilometre.

Looking over his shoulder and spotting a haze of blue and yellow, Chavanel just had enough in the tank to hold on for second place, 1:31 down on the stage winner Polanc. Aru picked up the final bonus seconds ahead of Contador and Porte to signal his intent after a fabulous opening five days on the Giro.

Thursday’s stage six should see a lull in the battle for GC: the 183km ride from Montecatini Terme to Castiglione Delle Pascaia includes a series of small peaks and one Cat.4 climb, but these challenges are followed by a flat final 50km which should pave the way for a bunch sprint.