Wout Poels unleashed a ferocious attack in the final kilometre of the imposing climb of Montee de Pipay, overtaking Jakob Fuglsang (Astana) and Emanuel Buchmann (BORA-hansgrohe) in the final few hundred metres to take an impressive victory.
"I attacked a few times and [the GC group] didn't let me go," said Poels, "then going into the final kilometre it was a case of now or never and I gave everything. I am normally quite good in the bad weather - maybe the best way to keep warm is to pedal faster! For some reason I always seem to go well in bad weather.'
Poels paid tribute to team leader Chris Froome, who crashed out during a recon of the time trial course with Poels ahead of Stage 4 and has been in Intensive Care in hospital since.
"It was hard to see what happened to Chris," said Poels, "obviously I was behind it when it happened, it gave me a little bit more motivation as he should be the leader, but then I had to take over. It’s really nice for the team to get a nice win and and it’s a gift for Chris."
Fuglsang took over the race lead with the second place finish behind Poels, coming in a second behind the Dutchman and taking the lead from previous race leader Adam Yates (Mitchelton-Scott), who was sixth on the day.
"One day to go, the legs are good so I’ll give it a good try to go for the overall win," said Poels, "but Fuglsang has been really good all year, he looks strong and he has a really good chance.”
The race got off to an aggressive start as Alexey Lutsenko (Astana) made the early 22-man break, with Mitchelton-Scott forced to chase hard to protect Yates' lead due to the Kazak's position on the general classification.
Lutsenko responded by attacking from the break alongside Michael Woods (EF Education First), with Michal Kwiatkowski (Team INEOS) bridging over to the escaped duo.
The trio were caught with four kilometres remaining in the race and Buchmann was the first to launch an attack, churning his way through the pouring rain as Fuglsang responded behind.
Yates defended his leader's jersey by upping the pace from the main group, receiving assistance from Thibaut Pinot (Groupama-FDJ) in setting the tempo but no one had an answer for Poels' acceleration.
Australian Richie Porte was distanced once Buchmann attacked and finished 14th on the stage, 46 seconds in arrears.