Ireland's Dan Martin agonisingly close to stage win at the Tour de France
Alexis Vuillermoz claimed the first French victory of the 2015 Tour de France by bursting to win stage eight atop the Mur de Bretagne.
The 181.5-kilometres eighth stage from Rennes finished at the summit of a climb which brutally ramps up for a kilometre before flattening out.
Race leader Chris Froome (Team Sky) made a burst in an attempt to show his dominance to his rivals for overall glory.
He felt he had done enough as Vuillermoz timed his surge expertly to triumph.
Birmingham-born Irishman Dan Martin (Cannondale-Garmin) was frustrated with himself in finishing second, five seconds back after a late attack, while Alejandro Valverde (Movistar) was third.
Vincenzo Nibali (Astana) lost some seconds to Froome as his title defence slipped further, giving the 2013 winner further momentum ahead of Sunday's team time-trial.
Froome remained 11 seconds clear of Peter Sagan (Tinkoff-Saxo), who was fourth on the stage.
Froome finished eighth on the stage, one place behind fellow Briton Adam Yates (Orica-GreenEdge).
Alberto Contador (Tinkoff-Saxo) and Nairo Quintana (Movistar) finished on the same time, in 14th and 17th place, respectively.
Contador remained 36 seconds adrift and Quintana one minute 56 seconds behind, but Nibali conceded 10 seconds to Froome.
Nibali was 20secs behind Vuillermoz and 10secs behind Froome's group in finishing in 30th place and dropping 1:48 adrift overall.
The day's early four-man escape comprised four riders - Bartosz Huzarski (Bora-Argon), Sylvain Chavanel (IAM Cycling), Romain Sicard (Europcar) and Pierre-Luc Perichon (Bretagne-Seche Environnement) - but racing began apace after the intermediate sprint.
There was a counter attack with 17 riders joining the four leaders, with three - Huzarski, Michal Golas (Etixx-QuickStep) and Lars Bak (Lotto-Soudal) - then breaking clear on their own.
The rest of the group was swept up as the trio held an advantage of around 30 seconds with 60km to go.
Huzarski was the final member of the breakaway to be caught, 10km from the finish, as the leading teams jostled for position ahead of the concluding ascent.
Froome's Team Sky squad was prominent 3km out, with Leopold Koenig on second wheel and the Briton right on his tail.
Geraint Thomas moved to the front to drag Froome along, but Giant-Alpecin made a move and next Simon Yates (Orica-GreenEdge) made a burst.
Froome was isolated, his team-mates' work done, but attacked with 1km to go, stringing out the select bunch which had formed.
Vuillermoz made his move, surprising the peloton.
Martin set off in pursuit, but left it too late to steal victory.