Australian Richie Porte has won stage four of the Paris-Nice just ahead of fellow Team Sky rider Geraint Thomas.
Porte and Welshman Thomas pulled clear in the final two kilometres of the 208km stage from Varennes-sur-Allier to the summit of Croix de Chaubouret.
Etixx-Quick-Step's Polish rider Michal Kwiatkowski produced a solo chase and finished eight seconds behind the pair.
Kwiatkowski's efforts ensured that he reclaimed the race lead with Porte one second back and Thomas in third.
Australian Michael Matthews had been the overnight leader after stage three but he slipped down to 74th spot overall after he dropped off the peloton and finished 14 seconds behind Porte.
Former Tour de France champion Sir Bradley Wiggins, who is riding in support of Thomas and Porte, has slipped to 128th overall after finishing more than 23 minutes behind the stage winner.
On Friday, the fifth stage takes the riders on a 192.5km route from Saint-Etienne to Rasteau, with few hill climbs to negotiate.
Paris - Nice stage four result
1. Richie Porte (Aus/Team Sky) 5hrs 18mins 39secs
2. Geraint Thomas (GB/Team Sky) Same time
3. Michal Kwiatkowski (Pol/Etixx-Quick-Step) +8secs
4. Jakob Fuglsang (Den/Astana)
5. Tejay van Garderen (US/BMC Racing) +17secs
6. Rui Costa (Por/Lampre) +24secs
7. Tony Gallopin (Fra/Lotto)
8. Fabio Aru (Ita/Astana)
9. Rafael Valls (Spa/Lampre)
10. Simon Spilak (Slo/Katusha)
Classification after stage four
1. Michal Kwiatkowski (Pol/Etixx-Quick-Step) 19hrs 44mins 11secs
2. Richie Porte (Aus/Team Sky) +1sec
3. Geraint Thomas (GB/Team Sky) +3secs
4. Tejay van Garderen (US/BMC Racing) +27secs
5. Jakob Fuglsang (Den/Astana) +32secs
6. Tony Gallopin (Fra/Lotto) +38secs
7. Rui Costa (Por/Lampre) +41secs
8. Gorka Izagirre (Spa/Movistar) +44secs
9. Tiago Machado (Por/Katusha) +50secs
10. Rafael Valls (Spa/Lampre) +51secs