Australia's Richie Porte was third in the sixth stage of the Paris-Nice as Briton Simon Yates attacked in the penultimate climb to put Julian Alaphilippe's overall lead came under threat.
Two-time winner Porte finished 26 seconds adrift of Yates and 17 behind Colombia's Sergio Henao, who was second. The Tasmanian, who finished third in last year's edition, sits 15th on the general classification with two stages to go and a third title appears unlikely.
Orica-Scott rider Yates jumped away from a group of leading riders near the top of the Col de Bourigaille, 20km from the finish line up the Mur de Fayence, a punishing climb at an average gradient of 9.8 per cent.
"I was quite far out in the general classification this morning so I had a bit of freedom," said Yates.
"I hoped I would be joined by other riders but I was on my own so I just had to go full gas until the end."
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Yates is now eighth overall, 1:37 behind Alaphilippe.
"If I wanted to win the GC I had to try and take time back somewhere," Yates said. "But there is still quite a lot of time to regain. Alaphilippe is a phenomenal rider, one of the most gifted of our generation."
Henao (Team Sky) attacked with 1km left to take second and finish second to move up to third overall, 46 seconds off the pace.
Henao is expected to further threaten Alaphilippe's lead in Saturday's decisive so-called "queen stage", a 177-km trek featuring three category-one ascents.
Alaphilippe (Quick Step Floors) ended up fourth on the day, 29 seconds behind Yates and 12 adrift of Henao, who also bagged six seconds in time bonuses.
Among the favourites, Spain's Alberto Contador (Trek Segafredo) and Russian Ilnur Zakarin (Katusha) finished 32 seconds off the pace.
