Britain’s Peter Kennaugh won stage seven of the Criterium du Dauphine, but defending champion Chris Froome lost time on leader Richie Porte.
Team Sky rider Kennaugh rode solo to the win on Alpe d’Huez, pulling away from compatriot Ben Swift in the final three kilometres to win by 13 seconds.
Australia’s Porte attacked at the end to gain 23 seconds on Britain’s Froome, who stays second.
He leads the Briton by one minute two seconds before Sunday’s final stage.
That will see riders tackle a punishing mountainous trek which ends on the summit of the Plateau de Solaison.
“To win at L’Alpe d’Huez is better than being an Olympic champion,” said Isle of Man rider Kennaugh, who won gold at London 2012 as part of the team’s pursuit.
The Tour de France, of which Froome is a three-time winner, starts on 1 July.
Stage seven results:
1. Peter Kennaugh (GB/Team Sky) 4hr 43min 59secs
2. Ben Swift (GB/UAE Team Emirates) +13 secs
3. Jesus Herrada (Spa/Movistar) +1min 11secs
4. Jelle Vanendert (Bel/Lotto) +1min 13secs
5. Romain Bardet (Fra/AG2R) +1min 14secs
6. Richie Porte (Aus/BMC Racing) +1min 56secs
7. Jakob Fuglsang (Den/Astana) Same time
8. Andrew Talansky (US/Cannondale) +2min 04secs
9. Alberto Contador (Spa/Trek) Same time
10. Fabio Aru (Ita/Astana) +2min 13secs
Chris Froome (GB/Team Sky) +2min 19secs
Overall classification after stage seven:
1. Richie Porte (Aus/BMC Racing) 25 hr 38mins 29secs
2. Chris Froome (GB/Team Sky) +1min 02secs
3. Jakob Fuglsang (Den/Astana) +1min 15secs
4. Fabio Aru (Ita/Astana) +1min 41secs
5. Alejandro Valverde (Spa/Movistar) +1min 43secs
6. Alberto Contador (Spa/Trek) +1min 55secs
7. Romain Bardet (Fra/AG2R) +2min 07secs
8. Daniel Martin (Ire/Quick-Step) +2min 31secs
9. Emanuel Buchmann (Ger/BORA) +2min 53secs
10. Andrew Talansky (US/Cannondale) +3min 43secs