Warren Barguil claimed victory on the final summit finish of the Tour de France on the day he mathematically secured the King of the Mountains jersey, while Chris Froome maintained his lead in the fight for the yellow jersey.
With just a flat stage and a time trial to go before the final processional run to the Champs-Elysees, the last mountain stage on Thursday looked as if it could be decisive in the battle for the overall win.
But instead the general classification winner will effectively be decided on Saturday as Team Sky's Froome, who went into stage 18 - a 179.5-kilometre ride from Briancon to Izoard - 27 seconds ahead, lost just four seconds to Romain Bardet (AG2R La Mondiale), who moved into second overall.
Further up the road it was Barguil (Sunweb) who took the acclaim on the climb up the Col d'Izoard, the polka dot jersey holder denying Darwin Atapuma a first individual Grand Tour stage triumph as he caught the Colombian and then surged clear in the final kilometre.
After an initial 54-man breakaway it was Astana's Andrey Lutsenko who reached the summit of the category-one climb of the Col de Vars - the second ascent of the day - first and he went clear of the rest of the field and started the route up Izoard alone.
However, he was eventually caught and dropped by BMC's Atapuma, who appeared set to end his drought on Colombian Independence Day, only for Barguil to dash his hopes and give the home fans more to celebrate.
All attention will now turn to Saturday's time trial as Bardet aims to bridge the 23-second gap to Froome having crossed the line just ahead of the Briton and receiving four bonus seconds as a result of finishing the stage third.
GOOD DAY / BAD DAY
As he did in his victory on Bastille Day on stage 13, Barguil proved to have the greater reserves of energy in the closing kilometres and can now relax knowing the polka dot jersey is his.
"It's really fantastic. It's a dream for me. Just unbelievable," Barguil told Eurosport after his triumph.
But Atapuma must wonder about what might have been, with second place the Colombian's only reward for a gruelling effort as he finished 20 seconds adrift of Barguil.
1. Chris Froome (Sky) 78:08:19
2. Romain Bardet (AG2R La Mondiale) + 0.23s
3. Rigoberto Uran (Cannondale) +0.29s
1. Michael Matthews (Sunweb) 364 points
2. Andre Greipel (Lotto Soudal) 204 points
3. Sonny Colbrelli (Bahrain-Merida) 163 points
KING OF THE MOUNTAINS
1. Warren Barguil (Sunweb) 169 points
2. Primoz Roglic (Lotto NL-Jumbo) 80 points
3. Thomas De Gendt (Lotto Soudal) 63 points
Friday's 222.5km stage from Embrun to Salon-de-Provence is the longest of the Tour and boasts a triumvirate of category-three climbs that will make it on tough on the legs.
It serves as the final opportunity for a breakaway rider to experience glory but - given how the GC race is poised - is likely little more than just an appetiser for the time trial in Marseille.