It was a dramatic stage of mechanicals, crashes, punctures and riders dropped over the long gravel sections of the Aube region in northeastern France.
Reusser and SD-Worx were one of the best-positioned teams after the hardest of the sectors, and it was Reusser that took advantage with an attack that saw her surge clear of the group of favourites.
“We did it," said Reusser, "The team had a plan to make it a hard race and to not let it come down to an easy finale. We said we would attack and one would go. Then I was lucky it was me.
"We have our GC leaders, we always keep them in front, but this team always has an open and aggressive strategy, so everybody is allowed to go for the win. We all work together, we help each other and we attack. I was the lucky one.
"This stage suits the kind of rider I am with these gravel sections. It was hard but it was not as hard as other stages for me."
While there were attacks behind, none got close to catching the European time trial champion and she won by a minute and 24 seconds as she consistently pushed out her lead all the way to the finish line in Bas-Sur-Aube.
A very large group got away in the first half of the stage with most teams represented, but it was brought back together relatively quickly.
Laura Asencio (Ceratizit-WNT), Coralie Demay (St Michel - Auber93), Valerie Demey (Liv Racing Xstra) got away with 83 kilometres to go. Demay survived the longest of the break over the initial gravel sectors, with the peloton dramatically reduced with the combination of hard climbs and mechanicals from the tough gravel sections.
Cecilie Uttrup Ludwig (FDJ-SUEZ-Futuroscope), Mavi Garcia (UAE-ADQ), Rachel Neylan (Cofidis) and Kasia Niewiadoma (Canyon-SRAM) all either held up by crashes or suffering mechanical issues.
The pace increased over the gravel sectors then slowed over the paved roads as teams re-grouped and returned from mechanical issues. Marlen Reusser used one of these lulls to launch her attack, surging down the side of the road and attacking to get a gap, with no immediate response until she’d gone clear.
While the surging in the gravel sections and climbs continued there was no consistent chase and Reusser’s lead got out to a minute as the Swiss time trial specialist powered on to the finish. Alena Amialiusik (Canyon-SRAM), Evita Muzic (FDJ-Suez-Futuroscope) and Veronica Ewers (EF Education-Easypost) attacked separately from the peloton to try to bridge across, eventually joining forces with 10 kilometres to go and 35 seconds to catch up on Reusser.
Reusser wasn’t a threat on the general classification after conceding over six minutes on previous days. She continued to build her stage lead over the final short climb and then she had just the technical descent and a short flat section to tackle to finish with the one of the biggest victories of her career.
Muzic crossed the line for second with Amialiusik third, and Marianne Vos leading the bunch home for fifth in the bunch sprint. Vos retained the overall lead by 16 seconds over Silvia Persico (Valcar Travel & Service) and Kasia Niewiadoma (Canyon-SRAM).
Ruby Roseman-Gannon (BikeExchange-Jayco) was the highest placed Australian on the day, finishing eighth on the stage as she continues her impressive neo-professional season, with Grace Brown (FDJ-Suez-Futuroscope) and Rachel Neylan (Cofidis) also in the main bunch.
The Tour de France Femmes continues with the longest stage of the race, a whopping 175.6 kilometres over mostly flat terrain. Watch on the SBS SKODA Tour Tracker from 10.15pm AEST on the SBS SKODA Tour Tracker with the SBS and SBS On Demand 10.30pm AEST.