Chris Froome retained the overall lead of the Tour de France and fellow Briton Adam Yates stayed second after a ferocious battle on a mountainous ninth stage won by breakaway rider Tom Dumoulin.
Froome (Team Sky), Yates (Orica-BikeExchange), Dan Martin (Etixx - Quick-Step), Richie Porte (BMC Racing) and Bauke Mollema (Trek-Segafredo) all launched multiple attacks on a thrilling 10km climb to the summit finish at Andorre Arcalis played out in torrential rain and hail.
But none of them could open up a decisive gap and they all crossed the finish line within two seconds of each other, as did Nairo Quintana (Movistar), who chased down every attack without making any of his own.
The day did, however, claim several casualties, with Fabio Aru (Astana) losing a minute to Froome, Tejay van Garderen (BMC Racing) losing 38 seconds and Alberto Contador (Tinkoff) pulling out of the race through illness.
The result means Froome stays 16 seconds ahead of second-placed Yates at the top of the general classification, while Martin is 19 seconds back in third and Quintana rises to fourth, 23 seconds adrift.
Dumoulin (Giant-Alpecin), meanwhile, formed part of a 20-man breakaway but moved into a solo lead with an attack 12.8km from the finish and hung on to beat Rui Costa (Lampre-Merida) and Rafal Majka (Tinkoff) into second and third respectively by 38 seconds.
Dumoulin, who has now won stages of all three grand tours in the past year, said: "It's a dream. It came true and I cannot even speak right now. I am so tired, but it was an incredible day. Queen stage, really hard, and I did it.
"I'm a time-trial specialist, but today I showed I can do more. I showed that already in the Vuelta last year, but I am so, so happy. It's incredible."
Stage nine was the last of three back-to-back days in the Pyrenees and ended with the first of the race's four summit finishes.
It initially looked like Contador was over the injuries he sustained in crashes on stages one and two when he launched an attack on the first climb, but he was quickly reeled back in and after reports emerged that he was suffering with a fever, the Spaniard quit the race with 100km to go.
The day's breakaway was whittled down from 20 to 10 ahead of the final climb, but then Dumoulin attacked on one of the last sections of flat road and was not seen again.
Eight minutes back, the peloton had earlier called a ceasefire after temperatures soared to a stifling 36C, but the truce ended with about 6km to go, when Porte and then Froome launched preliminary attacks as sunshine gave way to hail and rain.
Their moves lit a fuse in Martin, who subsequently launched four back-to-back attacks in a remarkable show of aggression, while Mollema also put in two digs.
But on every occasion they were chased down by a combination of Porte and particularly Froome, who was followed pedal stroke for pedal stroke by a vigilant and clearly comfortable Quintana.
Froome launched a final attack of his own and Yates also made a late acceleration, but the favourites ultimately crossed the line together in a sprint.
The stage was partly marred when a fan wandered into the road and collided with breakaway rider George Bennett (LottoNL-Jumbo), who was able to stay upright and continue.
The Tour now pauses for its first rest day on Monday, but the race resumes on Tuesday with a 197km 10th stage from Escaldes Engordany to Revel. Find out more about the route in our race guide and follow the stage live with our live blog from 1pm BST.
Stage nine result
1 Tom Dumoulin (Ned) Giant-Alpecin, 5:16:24
2 Rui Costa (Por) Lampre-Merida, +38sec
3 Rafal Majka (Pol) Tinkoff, same time
4 Daniel Navarro (Esp) Cofidis, +1:39
5 Winner Anacona (Col) Movistar, +1:57
6 Thibaut Pinot (Fra) FDJ.fr, +2:30
7 George Bennett (NZ) LottoNL-Jumbo, +2:48
8 Diego Rosa (Ita) Astana, +2:52
9 Mathias Frank (Sui) IAM Cycling, +3:44
10 Adam Yates (GB) Orica-BikeExchange, +6:35
Selected others
11 Chris Froome (GB) Team Sky, st
12 Nairo Quintana (Col) Movistar, st
13 Richie Porte (Aus) BMC Racing, +6:37
14 Dan Martin (Irl) Etixx - Quick-Step, st
General classification
1 Chris Froome (GB) Team Sky, 44:36:03
2 Adam Yates (GB) Orica-BikeExchange, +16sec
3 Dan Martin (Irl) Etixx - Quick-Step, +19
4 Nairo Quintana (Col) Movistar, +23
5 Joaquim Rodriguez (Esp) Katusha, +37
6 Romain Bardet (Fra) Ag2r-La Mondiale, +44
7 Bauke Mollema (Ned) Trek-Segafredo, st
8 Sergio Henao (Col) Team Sky, st
9 Louis Meintjes (RSA) Lampre-Merida, +55
10 Alejandro Valverde (Esp) Movistar, +1:01