A great Grand Tour is only decided on the final mountain stage, with one last battle coming on the final climbs of the race after three weeks of intense competition.
Before Friday's stage to Risoul, Steven Kruijswijk (LottoNL-Jumbo) seemed virtually unbeatable at this Giro d'Italia, not giving an inch to his rivals since taking the pink jersey in the Dolomites on the stage to Corvara a week ago. He led Esteban Chaves (Orica-GreenEdge) by three minutes, with Alejandro Valverde (Movistar) third at 3:23 and a crestfallen Vincenzo Nibali (Astana) a more distant fourth.
Yet Grand Tour racing can be turned on its head in just a moment, via an incident that jeopardises days and days of fatigue and effort. It can be a split-second, a moment of distraction, a desire to eat or drink at the wrong time. Suddenly the Giro d'Italia can flip, like Kruijswijk flipped over his bike and into the snow banking on Friday. It is both the beauty and the cruelty of Grand Tour racing.
As a consequence of his spectacular crash, Kruijswijk lost a massive 4:54 to stage winner Vincenzo Nibali (Astana) and 4:01 to new race leader Esteban Chaves (Orica-GreenEdge), who pulled on the maglia rosa as Kruijswijk nursed his wounds. Kruijswijk slipped to third overall at 1:05 and admitted he had lost his chance to become the first ever Dutch winner of the Giro d'Italia. Confirmation that he cracked a rib in the fall compounded his pain and will make it so much harder for him pull back enough time to move past Nibali and Chaves and back into pink.
Chaves could only smile and savour his moment in the pink leader's jersey, but he knows the Giro d'Italia is not over until Sunday. The Colombian and his Orica-GreenEdge mates will have to defend their 44 second advantage on a resurgent Nibali, keep their eye on Kruijswijk, and watch out as the other riders tussle for places on the podium and the final top five during Saturday's last big day out in the Alps.
Four big climbs and three long decents in 134km of racing
Stage 20 is only 134km long but is brutal because it includes four major climbs that mean riders face 63.5km and 4,100 vertical metres of climbing. To make matters worse, it all starts from the moment the flag drops in Guillestre. The French village is at an altitude of 1,005 metres, but the riders immediately climb to 2,108m via the Col de Vars. It is not steep but is 18.2km long with a profile that includes two steep steps separated by a flat middle.
It is followed by 20km of descending, which takes the riders down to 1,221m at Jausiers. It is the start of the big one, the 2,715m high Col de la Bonette that comes mid-stage. It is 22.2km long and rises constantly, with a central 16km section at over 7 per cent and a two-kilometre section – after 13km – at a painful 9 per cent.
The Col de la Bonette falls just short from being the highest climb, and so the 'Cima Coppi', of this year's Giro d'Italia. That honour went to the Colle dell'Agnello on Friday, but only by 29m. The Col del Bonette could be just as important as Friday's big climb.
Yet this final and decisive mountain stage does not end on the summit of the Col de la Bonette. The 40km descent takes the riders to Isola for the Colle della Lombarda. It is another beast of a climb - 19.8km at an average gradient of 7.5 per cent. The descent finally begins at the border between France and Italy, but after 10km of descending the road kicks up again for two-kilometres at 9 per cent as the race climbs to the finish in Sant'Anna di Vinadio.
It is likely that riders will reach the finish alone, fighting for every second, which will decide this year's winner and so the final maglia rosa.
White: 'I'm confident that Chaves is up to the challenge'
After stage 19 on Friday, Chaves spoke with what a seemed a blocked nose and may no longer be on his best form. The three big mountain climbs offer nowhere to hide and so will reveal any weaknesses. Despite his happy demeanour, Chaves has shown great maturity and tactical acumen during this year's Giro d'Italia. He now wears the maglia rosa, meaning his rivals have to attack him if they want to snatch overall victory.
"Now there are three riders within minute. That's incredible," Chaves said. "Today [Friday] we raced to attack, tomorrow [Saturday] we can ride to defend the jersey. So we can stay calmer, with our feet on the ground. It's also a short stage but a hard stage. We'll do everything we can to try to take the jersey home. It'll be ‘bellissimo' if we can; if not we'll have done our very best."
Fellow Colombian rider Rigoberto Uran promised he would help the national cause and help Chaves try to win the Giro d'Italia as he tries to win the stage and make up for his own illness-affected race. Chaves is only the third Colombian rider to pull on the pink jersey, after Uran and eventual winner Nairo Quintana in 2014.
The Orica-GreenEdge team is determined to finish off the job they have worked so hard for in 2016. The Giro d'Italia was set as a major goal after Chaves wore the leader's jersey at the Vuelta a España last year, winning two stages and finishing fifth overall.
"Tomorrow is going to be a very difficult stage and we are going to have to be on our guard all the time, but we have one more hard day to go and we are really happy to be in this position," directeur sportif Matt White said after the stage to Risoul.
"The stage to Sant'Anna di Vinadio is one of the hardest ways to finish off any Grand Tour but I'm confident that Chaves is up to the challenge."