Britain's Geraint Thomas remains in contention to win Paris-Nice after stage five, won by Alexey Lutsenko.
The Kazakh rider attacked around 15km from the end of the hilly stage, and stayed clear to win by 21 seconds.
Alexander Kristoff won the bunch sprint for second ahead of overall race leader Michael Matthews, who saw his advantage cut to six seconds by Lutsenko.
Team Sky's Thomas finished in the main bunch and is sixth, 23 seconds adrift of Matthews with two stages remaining.
Friday's stage featured a partial ascent of Mont Ventoux to Chalet Reynard, although it came too early in the 198km race to Salon-de-Provence to decide the winner.
It was on the third of the three category two climbs that followed, the Col de Seze, that Lutsenko made his break and the Astana rider, who also picked up 10 bonus seconds for winning the stage, moved up to second from 15th.
Orica GreenEdge's Matthews, who won four bonus seconds for finishing third, said: "I had noted this stage down as I was hoping we could get rid of the sprinters along the way but as we didn't, we sat back and let the other teams do the work.
"The priority was then the yellow jersey more than the stage win. I'm not going to say I can win Paris-Nice but I'm going to give it everything I have."
Saturday's penultimate stage features seven climbs, with a summit finish after a final 15.3km ascent.
Stage five result:
1. Alexey Lutsenko (Kaz/Astana) 5hrs 00mins 26secs
2. Alexander Kristoff (Nor/Katusha) +21secs
3. Michael Matthews (Aus/Orica GreenEdge) Same time
4. Davide Cimolai (Ita/Lampre)
5. Sep Vanmarcke (Bel/LottoNL)
6. Pieter Serry (Bel/ tixx - Quick-Step)
7. Vicente Reynes (Spa/IAM Cycling)
8. Leonardo Duque (Col/Delko)
9. Oliver Naesen (Bel/IAM Cycling)
10. Arnold Jeannesson (Fra/Cofidis)
19. Ben Swift (GB/Team Sky) Same time
22. Geraint Thomas (GB/Team Sky)
29. Alberto Contador (Spa/Tinkoff)
Overall classification after stage five:
1. Michael Matthews (Aus/Orica GreenEdge) 19hrs 24mins 58secs
2. Alexey Lutsenko (Kaz/Astana) +6secs
3. Tom Dumoulin (Ned/Giant) +18secs
4. Patrick Bevin (NZ/Cannondale) +23secs
5. Jon Izagirre (Spa/Movistar) Same time
6. Geraint Thomas (GB/Team Sky) Same time
10. Richie Porte (Aus/BMC Racing) +31secs
17. Alberto Contador (Spa/Tinkoff) +37secs
18. Simon Yates (GB/Orica GreenEdge) +41secs
19. Ben Swift (GB/Team Sky) +42secs