Nibali proved he was a class above, attacking from an ever-decreasing bunch on the brutal gradients despite having been isolated at the front as a result of Jakob Fuglsang suffering a heavy crash.
Alejandro Valverde (Movistar) and Thibaut Pinot (FDJ.fr) led the chasers, but Nibali’s acceleration was simply peerless as The Shark caught and passed the two leaders on the road – Leopold Konig (Team NetApp-Endura) and Rafal Majka (Tinkoff-Saxo) and cruised to victory with a phenomenal ride.
With second-placed Richie Porte (Team Sky) seeing his overall ambitions dealt a huge blow as he suffered on the final climb, dropping well out of contention, Nibali was left to celebrate taking another huge step closer to sealing his ‘holy trinity’ of career Grand Tour wins.
How it unfolded
There had been no shortage of riders looking to go clear early in the stage – a group containing Jens Voigt (Trek Factory Racing) and Alessandro de Marchi (Cannondale) among those not given license to attack.
When a nine-man group eventually went clear it was a strong one though – de Marchi again part of it, alongside the likes of Daniel Oss (BMC Racing) and Giovanni Visconti (Movistar).
Jan Bakelants (Omega Pharma-Quickstep) bridged to join the group, alongside Rudy Molard (Cofidis), with Brice Feillu (Bretagne-Seche Environnement), Kristijan Durasek (Lampre-Merida) and Bartosz Huzarski (Team NetApp-Endura) already there.
It was the presence of Blel Kadri (Ag2r-La Mondiale) in the group however, a rider in contention for the polka dot jersey, which put paid to any hopes of them staying out.
Protecting Joaquim Rodriguez’s mountains lead, Katusha set a furious pace and by the time the break had reached the category-one Col de Palaquit it was already splintered.
De Marchi remained at the front, with Bakelants hovering further back but the remains of the break were quickly swallowed up by the bunch as the fastest projected time was shattered by the pace of the bunch.
Kadri was caught and spat right back out again, while the sprinters did not take long to crack as the peloton shredded rapidly.
De Marchi crossed the summit first, climbing well and descending even better to stay out in front – despite a bike change for Bakelants at the top – while Luis Angel Mate (Cofidis) made an attempt to join them.
Mate’s rapid descent almost cost him dearly, however, as he rode far too wide on a bend and narrowly avoided a collision with the barriers.
Rodriguez meanwhile led the bunch over the summit, with Nibali having lost several team-mates on the ascent in the same group.
It got worse, too, for the race leader when right-hand man Jakob Fuglsang collided with a bidon on the descent, crashing heavily at speed.
Movistar were the team who looked to take advantage once the roads levelled out and headed towards the final ascent.
John Gadret came forward and set a phenomenal pace on the lower ramps of the 18.2 kilometre climb – which boasts average gradients of more than seven per cent.
Rodriguez was among the riders shelled out the back on the climb, as Bakelants was caught and passed with ease to leave just de Marchi up the road in front.
Team Sky had boasted three riders in the bunch, all of whom had looked comfortable, but no sooner had Bakelants been caught than Geraint Thomas joined him in sliding out the back, with Nico Roche (Tinkoff-Saxo) another unable to cope with the pace set at the front.
Such a fierce pace continued as De Marchi, too, was quickly reeled in and Team Sky’s Tour finally unravelled at the same time.
Sat second overall, Porte dropped to the back of the bunch as he talked into his race radio with his one remaining team-mate, Mikel Nieve, joining.
Though initially looking comfortable, it quickly became apparent the Australian – often so strong on the early mountain stages when riding in support of Chris Froome and Sir Bradley Wiggins in the past – was in trouble.
He rapidly lost contact with the front group, with Nibali – well aware of the situation as he looked over his shoulder – happy to burn out his last remaining team-mate, Tanel Kangert, to quickly send the front group disappearing into the distance ahead of Porte.
Porte being dropped prompted the remaining riders in the front group to start the attacks, Pinot being the first man to go clear as Valverde and Nibali checked his move.
Kangert and Pierre Rolland (Team Europcar) were among the riders caught out by the upping of pace as the lead group continued to splinter on the ten per cent sections.
Konig and Majka were next to go, earning a small lead, as the counter-attacks continued behind them.
It was Valverde who actually instigated the decisive move, earning a few bike lengths lead which Nibali and Pinot were quick to shut down before Laurens ten Dam (Belkin) joined them up the road.
The four were happy to work together as the kilometres ticked by, with Konig and Majka still leading before Nibali put in a huge dig with 6.5 kilometres remaining.
Further back, the counter-attacks continued as Romain Bardet (Ag2r-La Mondiale) and Tejay van Garderen (BMC Racing) both looked to seize the opportunity to move up overall.
Frank Schleck (Trek Factory Racing) also remained in one of the many small groups towards the front of the race.
The day, however, undoubtedly belonged to Nibali who barely broke stride as he caught Konig and Majka with no problem at all and soloed through the final six kilometres or so, increasing his overall lead by the pedal stroke.
His smooth rhythm masked the effort he was putting out, which only became obvious as he had barely the energy to raise his hands as he zipped up his jersey and crossed the line alone.
The riders continued to cross in ones and twos further back as the GC was given a huge shake-up, Valverde losing 50 seconds, van Garderen and Bardet 1’23”.
Michal Kwiatkowski, meanwhile was more than four minutes back while Thomas, Nieve and Porte lost eight minutes and 48 seconds to the Astana man.
It leaves the Italian with a commanding lead of three minutes and 37 seconds over Valverde, and a further 47 seconds over Bardet as the race prepares for another brutal day on stage 14, the Queen Stage of this year’s Tour.
Tour de France 2014: stage 13 – result
1) Vincenzo Nibali (ITA) – Astana – 5.12.29hrs
2) Rafal Majka (POL) – Tinkoff-Saxo +10”
3) Leopold Konig (CZE) – Team NetApp-Endura +11”
4) Alejandro Valverde (ESP) – Movistar +50”
5) Thibaut Pinot (FRA) – FDJ.fr +53”
6) Tejay van Garderen (USA) – BMC Racing +1.23
7) Romain Bardet (FRA) – Ag2r-La Mondiale – ST
8) Laurens ten Dam (NED) – Belkin Pro Cycling +1.36
9) Jean-Christophe Peraud (FRA) – Ag2r-La Mondiale +2.09
10) Frank Schleck (LUX) – Trek Factory Racing – ST
1) Vincenzo Nibali (ITA) – Astana – 56.44.03hrs
2) Alejandro Valverde (ESP) – Movistar +3.37
3) Romain Bardet (FRA) – Ag2r-La Mondiale +4.24
4) Thibaut Pinot (FRA) – FDJ.fr +4.40
5) Tejay van Garderen (USA) – BMC Racing +5.19
6) Jean-Christophe Peraud (FRA) – Ag2r-La Mondiale +6.06
7) Bauke Mollema (NED) – Belkin Pro Cycling +6.17
8) Jurgen van den Broeck (BEL) – Lotto-Belisol +6.27
9) Rui Costa (POR) – Lampre-Merida +8.35
10) Leopold Konig (CZE) – Team NetApp-Endura +8.36
16) Richie Porte (AUS) – Team Sky +11.11
18) Geraint Thomas (GBR) – Team Sky +14.05