Remco Evenepoel's Vuelta a Espana defence collapsed Friday after he was dropped by a big group early into stage 13, won by Jonas Vingegaard on a superb day for Jumbo-Visma.
The Belgian Soudal-QuickStep rider started the day third but trudged to the finish over 27 minutes behind Vingegaard, after losing contact on the climb towards the Col d'Aubisque summit with nearly 90 kilometres remaining.
Sepp Kuss kept the red jersey as he came in second, with Primoz Roglic completing a Jumbo-Visma podium in third -- all three riders have now won a stage each.
Roglic trails Kuss by one minute 37 seconds overall, with Vingegaard third, one minute 44 behind the leader.
"I couldn't choose a better day, today is the birthday of my daughter and I wanted to win for her so bad today," Vingegaard told Eurosport.
"Our plan was to see if we could take some time on the opponents today, that happened and I'm just so happy and proud to do it today, this one is for my daughter Frida.
"It went even better than the plan."
Evenepoel also pulled out of the Giro d'Italia in May, which he was leading, after testing positive for Covid just hours after winning the stage nine individual time trial.
The 23-year-old took the red jersey early on in the Vuelta but decided to lose it in stage six, conceding the lead to Lenny Martinez.
However, he showed signs of weakness as he also lost time to his main general classification rivals.
Kuss took the red jersey in stage eight and has maintained it since, even though back-to-back Tour de France winner Vingegaard and three-time Vuelta champion and Giro winner Roglic are Jumbo-Visma's leaders.
The Dutch team are aiming to become the first to win all three Grand Tours in a single season and Evenepoel's collapse has given them a fantastic chance.
Stage 13 always appeared key in the general classification battle, featuring over 4,000 metres of climbing in the Pyrenees.
It is one of the toughest stages of any of the Grand Tours despite its shorter length of 135 kilometres between Formigal and regular iconic Tour de France summit Col du Tourmalet.
Evenepoel was dropped relatively early, along with UAE Team Emirates rider Joao Almeida, who came in nearly seven minutes behind the Danish stage winner. Martinez also fell away with 20 kilometres to go.
Vingegaard attacked with eight kilometres to go and nobody could catch him, with Kuss leaving Enric Mas behind after with a superb burst, with Roglic coming in third.
Marc Soler, who started the day 26 seconds behind Kuss in second place is now sixth, over three minutes behind, trailing Spanish compatriots Juan Ayuso and Mas, fourth and fifth respectively.
In stage 14 on Saturday riders face another tricky stint in the mountains, between Sauveterre de Bearn and Larra-Belagua.
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