Soren Kragh Andersen claimed his second stage win of the Tour de France as Primoz Roglic stayed in pole position to claim the yellow jersey.
Andersen, who also prevailed on stage 14, took stage 19 with an attack 16 kilometres from the finish line of the 166.5-kilometre ride from Bourg-en-Bresse to Champagnole.
It was an attack to which the chasing pack had no answer, the Team Sunweb rider quickly building an insurmountable advantage.
He crossed the line 53 seconds ahead of his nearest challengers, but the focus will now shift firmly to Roglic and the overall race leader's Slovenian compatriot Tadej Pocagar.
That pair finished back in the peloton, over seven and a half minutes adrift of Kragh Andersen.
Roglic (Jumbo-Visma) remains 57 seconds ahead of Pogacar (Team Emirates) with Miguel Angel Lopez (Astana) a further 30 seconds back.
They will battle it out for the general classification in Saturday's time trial before the Tour comes to an end with a processional final flat stage to the Champs-Elysees in Paris.
Kragh Andersen's previous victory, on a flat stage from Clermont-Ferrand to Lyon, saw him attack three kilometres from the finish.
His push for victory this time, from a 12-man group at the front after Matteo Trentin (CCC Team) failed with an attack, was more ambitious but no less effective as he had plenty in his legs to surge clear.
As he entered the final kilometres, Kragh Andersen could be heard asking for confirmation of his time gap, unaware of the massive lead he had built.
He never had any need to worry about his victory being threatened, the Dane well worthy of the plaudits he will take before the battle for the GC crown takes centre stage.
KRAGH ANDERSEN'S UNBELIEVABLE LEAD
Kragh Andersen was left stunned by the decisive nature of his advantage, saying in his post-race interview: "In the last kilometre, when I was screaming 'Can you confirm one minute?', I didn't believe it."
Of his attack, he said: "I was thinking the same... 'Here's all the best riders in the world, how do I beat these guys?'. I was thinking, 'If I get a small gap maybe they start looking at each other', that's what happened.
"Two wins in the Tour de France... I'm speechless. It's a memory for life. I'm just super happy."
1. Soren Kragh Andersen (Team Sunweb) 3:36:33
2. Luka Mezgec (Mitchelton-Scott) +0:53
3. Jasper Stuyven (Trek-Segafredo)
4. Greg Van Avermaet (CCC Team)
5. Oliver Naesen (AG2R La Mondiale)
1. Primoz Roglic (Jumbo-Visma) 83:29:41
2. Tadej Pogacar (Team Emirates) +0:57
3. Miguel Angel Lopez (Astana) +1:27
1. Sam Bennett (Deceuninck-Quick-Step) 319 points
2. Peter Sagan (Bora-Hansgrohe) 264
3. Matteo Trentin (CCC) 250
King of the Mountains
1. Richard Carapaz (Team INEOS) 74
2. Tadej Pogacar (Team Emirates) 72
3. Primoz Roglic (Jumbo-Visma) 67
The Tour will effectively be decided by Saturday's penultimate stage, which takes the form of a mountain time trial from Lure to La Planche des Belles Filles.