Defending champion goes on attack to take leader's jersey from Chris Froome with just tomorrow's short time trial to come...

Vincenzo Nibali, winner of Tirreno Adriatico 12 months ago, looks poised to win the race for the second year running, the Astana rider  attacking towards the end of a deceptively tough stage won by Cannondale's Peter Sagan to put race leader Chris Froome in serious trouble and take the maglia azzurra.

The Sicilian finished second to former team mate Sagan, with whom he had attacked on the descent from Sant Elpidio a Mare with 17.5 kilometres left along with another of the best descenders in the peloton, Samuel Sanchez of Euskaltel. Sanchez would drop back in the final kilometres, with Sagan and Nibali joined by Katusha's Joaquin Rodriguez, who finished third.

With tomorrow's closing time trial only 9.2 kilometres long, Froome, who lost nearly a minute today, is 34 seconds behind Nibali in the overall standings and only has a remote chance of getting the race lead back.

Today’s parcours had a saw-toothed profile and comprised two 90 kilometre loops followed by a 28 kilometre circuit. It looked complicated enough on the map, but proved to be brutal on the road.

While riders including Mark Cavendish decided to sit out the stage altogether to begin preparing for Milan-San Remo, and others including Andy Schleck abandoned early on, the remainder had to cope not only with a series of sharp climbs, but also roads made slippery from rain that started falling after the day’s racing had begun.

The most imposing of today’s climbs, ridden three times, was to Sant Elpidio a Mare, where the gradient in the final 300 metres averaged 18 per cent but, at its steepest part, nudged 30 per cent.

On the second time over that summit, with 45.7 kilometres left to ride, Lampre-Merida’s Damiano Cunego was the first man across, in the process sealing his victory in the mountains competition in this year’s race.

The Italian was one of a large breakaway group that got away early on and which included big names such as Fabian Cancellara of RadioShack-Leopard, AG2R’s Rinaldo Nocentini, Movistar’s Giovanni Visconti and Blanco’s Lars Boom.

By the time the Sant Elpidio a Mare climb was tackled for the third and final time, from a different direction the GC group had swept up most of the escapees and there were just 17.5 kilometres left to ride.

The last survivor from the break, Movistar’s Benat Intxausti, was joined by three of the peloton’s best descenders on the way back down towards the finish –Nibali, Sanchez and Sagan, who had struggled on one of those earlier ascents to Sant Elpidio a Mare, zig-zagging across the road.

Behind, the field had split to pieces and race leader Froome was in trouble, as was Saxo-Tinkoff’s Alberto Contador, both isolated from their team mates, although it was the Team Sky man who was further back.

Ahead of the finish, Froome managed to get back to the second group, but the damage to his GC hopes had already been done.

One final ascent, which came 10 kilometres out, gave Joaquin Rodriguez of Katusha, winner in Chieti yesterday, the opportunity to get across to the front group, where only Nibali and Sagan remained.

The flat final four kilometres to the finish gave the trio plenty of time to work out the permutations, and it was of no surprise that Sagan took his second stage win of the week – not that Nibali or Rodriguez would have been able to match his acceleration – nor that the Astana rider was able to cross second to pick up more bonus seconds.

Tirreno Adriatico Stage 6 result

1.  Peter Sagan            Cannondale                5:46:17

2.  Vincenzo Nibali        Astana                       at 2

3.  Joaquim Rodríguez      Katusha
4.  Mauro Santambrogio     Vini Fantini                at 44

5.  Samuel Sánchez         Euskaltel-Euskadi
6.  Chris Horner           RadioShack-Leopard 

7.  Alberto Contador       Team Saxo-Tinkoff
8.  Jurgen Roelandts       Lotto-Belisol               at 50

9.  Thor Hushovd           BMC
10. Simon Geschke          Argos-Shimano

Overall standings after Stage 6

1.  Vincenzo Nibali        Astana                   27:57:26

2.  Chris Froome           Sky                         at 34 

3.  Joaquin Rodríguez      Katusha                     at 37

4.  Alberto Contador       Team Saxo-Tinkoff           at 48 

5.  Michal Kwiatkowski     Omega Pharma-Quick Step     at 58

6.  Chris Horner           RadioShack-Leopard        at 1:05

7.  Mauro Santambrogio     Vini Fantini              at 1:20

8.  Przemyslaw Niemiec     Lampre-Merida             at 2:54

9.  Andrey Amador          Movistar Team             at 2:58

10. Wouter Poels           Vacansoleil-DCM           at 3:08

Born in Scotland, Simon moved to London aged seven and now lives in the Oxfordshire Cotswolds with his miniature schnauzer, Elodie. He fell in love with cycling one Saturday morning in 1994 while living in Italy when Milan-San Remo went past his front door. A daily cycle commuter in London back before riding to work started to boom, he's been news editor at road.cc since 2009. Handily for work, he speaks French and Italian. He doesn't get to ride his Colnago as often as he'd like, and freely admits he's much more adept at cooking than fettling with bikes.