The French climber, who lost 11 minutes on stage 4, joined the breakaway of the day and rode all her companions off her wheel on the hard finishing climb.
Labous increased her advantage over the favourites' GC group to over two minutes and rode within her means, eventually winning the stage by 1:37 minutes.
The favourites' group was whittled down as rider after rider couldn't follow the pace, but none of the attacks really stuck, and six riders were still together in the final kilometre when race leader Annemiek van Vleuten (Movistar) launched her final attack.
Only Mavi García (UAE Team ADQ) and Marta Cavalli (FDJ Nouvelle-Aquitaine Futuroscope) tried to follow the maglia rosa, but Van Vleuten shook them both off and crossed the finish line in second place, taking a few seconds on her competitors.
"I was a bit scared because the gap was going down really fast, so I had to go full from the bottom. I saw that I was the strongest, so I just decided to take my own pace and to just go as hard as I could," said Labous.
"I am so happy with this win and will enjoy it. Tomorrow, I will maybe be a bit tired from today, but I will try to go for another stage win."
How it unfolded
Heading into the mountains after three laps of a local circuit in Prevalle, stage 7 finished with a climb up the Passo Maniva. After a long false flat up an Alpine valley, the last 9.9 kilometres climbed at an average 7.8%, with several sections much steeper than that. Stage 6 winner Marianne Vos (Team Jumbo-Visma) was one of five riders not starting the stage.
A large breakaway of 14 riders formed on the local laps, and the peloton let the time gap run to over nine minutes with 50km to go on the 112.9-kilometre stage before starting the chase.
When Amalie Lutro (Uno-X Pro Cycling Team) attacked from the break with 24km to go, the gap had been reduced to 7:28 minutes. The Norwegian built an advantage of 48 seconds on her former companions while Movistar Team and FDJ Nouvelle-Aquitaine Futuroscope did most of the work in the peloton that continued to close in on the break.
Lutro was caught by Cristina Tonetti (Top Girls Fassa Bortolo) within 500 metres of the climb starting for real, and 9km from the finish, only Labous, Mikayla Harvey (Canyon-SRAM), Paula Patiño (Movistar Team), Georgia Williams (Team BikeExchange-Jayco), Tonetti, and Magdeleine Vallieres (EF Education-TIBCO-SVB) were left in front.
Their advantage had fallen to only two minutes, and Labous decided that something needed to be done. Increasing the pace, the French climber rode everyone off her wheel until she was solo with 7.6km still to climb. Seven kilometres from the finish, Labous was 1:39 minutes ahead of the group of favourites that still counted 19 riders. Cecilie Uttrup Ludwig (FDJ Nouvelle-Aquitaine Futuroscope) and Erica Magnaldi (UAE Team ADQ) were setting the pace for their teammates Cavalli and García, picking up riders from the breakaway.
At the five-kilometre mark, Labous had increased her lead to 2:13 minutes again while the group behind was slowly, but surely thinned out. When Patiño was caught, she took a turn at the front of the group to set up an attack by Van Vleuten.
The maglia rosa’s attack split the favourites’ group into twos and threes, with only García and Cavalli able to keep up, but as Van Vleuten couldn’t shake her closest competitors, the pace fell again, allowing Elisa Longo Borghini (Trek-Segafredo), Gaia Realini (Isolmant-Premac-Vittoria), Amanda Spratt (Team BikeExchange-Jayco), and Niamh Fisher-Black (Team SD Worx) to return.
García attacked with just over two kilometres left of the climb, followed by Van Vleuten and Cavalli, and Van Vleuten herself continued the attack when García sat down, but again the maglia rosa could not get away.
Longo Borghini returned to the trio of favourites and immediately tried to attack but could not get away. Fisher-Black and Realini also came back on the final kilometre, and Fisher-Black took the lead of the group while Labous was riding to a solo victory up ahead.
Van Vleuten made her last attack on the steep slopes before the finish and gained four seconds on García and ten seconds on Cavalli plus six bonus seconds for second place, further increasing her GC lead.
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Lukas Knöfler started working in cycling communications in 2013 and has seen the inside of the scene from many angles. Having worked as press officer for teams and races and written for several online and print publications, he has been Cyclingnews’ Women’s WorldTour correspondent since 2018.