Chris Froome sensationally moved into pole position for Giro d'Italia glory with a ride for the ages as long-time leader Simon Yates tumbled out of the top 10 on a remarkable 19th stage.
Yates began the penultimate day of serious racing holding a 28-second lead over his nearest rival, defending champion Tom Dumoulin, only to falter spectacularly on the day's first major climb when Team Sky forced the pace and Froome launched the boldest of attacks up the Colle Delle Finestre with 80 kilometres remaining.
Froome - the reigning Tour de France and Vuelta a Espana champion who is seeking to complete a 'Triple Crown' of Grand Tour wins - duly kicked on from a chasing group that featured Dumoulin, winning the stage by three minutes.
Dumoulin came home fifth and now trails Froome by 40 seconds in the general classification, with every other rider at least four minutes back. Mitchelton-Scott rider Yates is totally out of contention after losing more than half an hour on Friday.
Having claimed the Maglia Rosa with arguably the finest ride of his illustrious career, Froome now faces the challenge of holding off Dumoulin on Saturday's penultimate stage, which is followed by a ceremonial finale.
Froome is still awaiting a verdict on the adverse analytical finding he provided en route to winning last year's Vuelta, although both he and Team Sky vehemently deny any wrongdoing.
There was an unwelcome reminder of the controversy for Froome, who had double the permitted level of an asthma medication in his urine at the Vuelta, as a spectator briefly ran alongside him on Friday carrying a giant inhaler.
IT WAS NOW OR NEVER - FROOME
Reflecting on his magnificent attack and subsequent victory, Froome said: "I just felt good and felt it's now or never. I don't think I've ever attacked with 80 kilometres to go on my own like that. The team did such a fantastic job to set that up for me.
"It was going to take something special today ... to go from fourth to first, I wasn't going to do that on the last climb alone, so I had to try from far out.
"It's great [to have claimed the Maglia Rosa]. Obviously there's still a really hard day [to come] tomorrow but the legs are feeling good and I've been feeling better and better as this race has gone on. Hopefully we can finish this off now."
Prior to the day's main drama, Fabio Aru made an early exit from proceedings, bringing his disappointing race to a premature end.
1. Chris Froome (Team Sky) 5:12:26
2. Richard Carapaz (Movistar) +3:00
3. Thibaut Pinot (FDJ) +3:07
4. Miguel Angel Lopez (Astana) +3:12
5. Tom Dumoulin (Team Sunweb) +3:23
1. Chris Froome (Team Sky) 80:21:59
2. Tom Dumoulin (Team Sunweb) +0:40
3. Thibaut Pinot (FDJ) +4:17
1. Elia Viviani (Quick-Step Floors) 290
2. Sam Bennett (Bora-Hansgrohe) 232
3. Davide Ballerini (Androni Giocattoli-Sidermec) 119
King of the Mountains
1. Chris Froome (Team Sky) 123
2. Simon Yates (Mitchelton-Scott) 91
3. Thibaut Pinot (FDJ) 70
Saturday's penultimate stage essentially decides the event, with the final stage effectively a ceremonial one. It remains to be seen how much Froome has left in the tank.
|Confident Moeen ready to shine for England in the Caribbean|
|Juventus 3 Chievo 0: Allegri´s men cruise despite Ronaldo penalty save|
|BREAKING NEWS: Boateng completes shock Barcelona switch|
|United Arab Emirates 3 Kyrgyzstan 2 (after extra time): Khalil penalty sets up Socceroos showdown|
|West Indies add Drakes to new-look coaching team|
|Barcelona is a huge opportunity – Boateng confirms shock move is close|
|Donnarumma wishes Higuain luck ahead of expected Chelsea switch|
|Qatar v Iraq: Katanec anticipating ´huge challenge´ in last 16|
|Nuno hit with FA misconduct charge for pitch celebration|
|Furious Carreno Busta and Zverev bow out, Djokovic marches on|
|#NotMartinFromWakefield – Siewert shows viral sensation the door|
|Djokovic feeling the strain after late-night Medvedev battle|
|Henderson sidelined again ahead of Six Nations|
|Australia 0 Uzbekistan 0 (aet, 4-2 on penalties): Ryan heroics see holders hobble onwards|
|Halep exit leaves four-way fight to be crowned number one at Australian Open|
|Super Bowl-bound Rams set for London return, Chiefs to face Chargers in Mexico|
|Huddersfield appoint Siewert as Wagner´s replacement|
|Genoa 0 AC Milan 2: Borini and Suso step up with Higuain left out|
|McTominay signs new Manchester United contract|
|Pizzi to stand down after Saudi Arabia elimination|
|Boateng closing in on shock Barcelona switch - reports|
|Catalans to defend Challenge Cup after resolving RFL dispute|
|Djokovic wears down Medvedev to reach last eight|
|Mouratoglou: I knew ´loyal´ Serena would not fire me after US Open turmoil|
|Barcelona B defender Wague accuses Ejea fans of racist abuse|
|I felt like I had been hit by a train - Halep upbeat despite losing Serena battle|
|Arsenal confirm Mislintat departure|
|Icardi will renew, 100 per cent - Wanda Nara offers latest Inter assurance|
|Japan 1 Saudi Arabia 0: Four-time winners send Pizzi´s men out|
|A souvlaki maybe named after him, a growing fan base – Tsitsipas creating Melbourne buzz|
|Barca winger Dembele out for 15 days|
|Strikers blown away by Hurricanes in Adelaide|
|Ireland lose Beirne for England and Scotland clashes|
|´Innate fighter´ Serena says character key to beating Halep|
|Hudson-Odoi ´an outstanding talent´ - Bayern great Ballack hails Chelsea youngster|
|Scotland call up four as hand injury forces Watson out|
|Serena comes through major Halep battle to reach last eight|
|Better than Rafa? Camacho cameo leaves Klopp unconvinced by transfer options|
|England job ´a privileged position´, says Southgate|
|Emery has confidence in Arsenal outcast Ozil|
|Zverev destroys racquet in Aus Open meltdown|
|From Villarreal to Aus Open quarters – Bautista Agut breaks major duck|
|Brees: I plan on being here next year and making another run at it|
|´Unf******-believable bro!´ - Brady stunned after reaching third straight Super Bowl|
|New England find answers, penalty costs Kansas City – three takeaways from Patriots´ win over Chiefs|
|Donald Trump congratulates Brady and Super Bowl-bound Patriots|
|Rose helps Timberwolves down Suns|
|Brady leads Patriots into third straight Super Bowl|
|Osaka overcomes Sevastova to reach quarters|
|Chelsea remain behind Sarri – David Luiz|
|McVay explains Gurley´s limited role in Rams´ win over Saints|
|Southgate hails ´tremendous talent´ Rashford|
|Long earns maiden PGA Tour win at Desert Classic|
|Flanagan resigns as Sharks head coach|
|Rams´ Robey-Coleman admits he committed penalty on controversial no-call|
|NFL admits they blew the call – Saints coach Payton|
|Terrible no-call, Goff shines – three takeaways from Rams´ win over Saints|
|Lonzo Ball to miss 4-6 weeks with ankle sprain|
|Patterson added to Australia Test squad|
|Zuerlein´s overtime kick sinks Saints and sends Rams to Super Bowl|
|It was a clear goal – Valverde dismisses Barca VAR controversy|
|Rashford can emulate Man United greats Ronaldo and Rooney – Solskjaer|
|Karmichael Hunt swaps Reds for Waratahs|
|Barcelona forward Dembele set for tests on sprained ankle|
|Neymar insists Barcelona and Real Madrid links not ´concrete´|
|England trio Nowell, Slade and Cowan-Dickie sign fresh Exeter deals|
|Windies coach Pybus not distracted by detractors|
|Barcelona 3 Leganes 1: Messi and Suarez combine to spare Barca´s blushes|
|I´m sure Michael would be extremely proud - Vettel hails Mick Schumacher|
|Young plays down injury fears for England trio Launchbury, Shields and Hughes|