Lennard Kamna landed his first Tour de France stage victory on a day when the overall race leaders saved their legs for what could be a make-or-break Wednesday.
As Germany's Kamna celebrated his maiden triumph, the picture at the top of the general classification after stage 16 remained unchanged, with Primoz Roglic and Tadej Pogacar remaining 40 seconds apart.
The peloton arrived at Villard-de-Lans a full 16 minutes and 48 seconds after Kamna crossed the line, having shown no interest at any time in following the breakaway pack.
Two monumental climbs in stage 17 could prove telling, so there was no need to exert excess energy on the 164-kilometre ride from La Tour-du-Pin.
It was nonetheless a day where a gaggle of riders out of GC contention took the opportunity to shine.
An early breakaway grew into a 23-rider squadron, splintering intermittently as the stage progressed.
Quentin Pacher made a solo break from the pack as they began the ascent to the town of Saint-Nizier-du-Moucherotte, which in 1968 hosted Olympic ski jumping, but he could not sustain the increase in pace.
The testing category one climb caught up with the Tour debutant, and his bold dart was reined in by four others, with Ecuador's Richard Carapaz (Team INEOS) leading the next burst that shook off Frenchman Julian Alaphilippe.
Kamna (Bora-Hansgrohe) and Swiss Sebastien Reichenbach (Groupama-FDJ) followed him, and it was Kamna who sprinted away to take the king of the mountain points, with Pierre Rolland having earlier claimed priceless points when he was first to climb the Cote de Revel.
This break was to prove decisive, with Kamna powering ahead on the open road to take the line first, a minute and 27 seconds ahead of Carapaz, with Reichenbach in third spot, 29 seconds further adrift.