Briton Bradley Wiggins finished sixth on the penultimate stage of the Criterium du Dauphine to go into the final day holding the overall lead.
The Team Sky rider crossed the line ahead of ninth-placed Cadel Evans, who trails Wiggins by 86 seconds, with Alexander Vinokourov in third place.
Spain's Joaquim Rodriguez won the 192.5km stage after he broke away from the pack with five kilometres to go.
The 117.5km final mountain stage takes place on Sunday.
Rodriguez's time of 5hr 12min 47sec was 31 seconds faster than second-placed Robert Gesink, with Wiggins 54.7sec adrift of the Team Katusha rider.
The gruelling stage ended with an 11.2km ascent at an average gradient of 8.4% up the Collet d'Allevard, but Wiggins, not known as a climber, displayed superb resilience in the hills in southern France as his rivals attempted to unsettle him from top spot.
Vinokourov, in third place overall, closed the gap on second-placed Evans but the Astana rider remains one minute and 52 seconds behind Wiggins.
Defending champion Janez Brajkovic lost more than three minutes on Wiggins, falling to ninth place and more than four minutes behind the leader.
A group of eight riders made the break about 80km into the stage, opening a four-minute gap on the peloton, with Team Sky controlling the pace at the front.
A herd of wandering cows caused some riders to swerve and crash, including Euskaltel's Mikel Landa, who was forced out of the race because of injury.
The peloton caught the breakaway group at the bottom of the final climb, with Wiggins expertly marshalled by his team-mates as Rodriguez accelerated to the stage win, his second of the year.
Wiggins extended his lead over Australian Evans by 15 seconds going into the Pontcharra to La Toussuire stage, which includes a ride up the Croix de Fer pass before another uphill finish.
Meanwhile, four-time world champion Fabian Cancellara won the opening stage time trial at the Tour of Switzerland for the fourth time.
The Swiss Leopard Trek rider clocked nine minutes 41.8secs through the hilly Lake Lugano course.
American Tejay Van Garderen of HTC-Highroad finished second with Slovakia's Peter Sagan, of Liquigas, in third place.
Criterium du Dauphine overall standings
1. Bradley Wiggins (GBR/Team Sky) 23 hrs 16 mins 11s
2. Cadel Evans (Aus/BMC Racing) +1min 26sec
3. Alexandre Vinokourov (KZH/Astana) +1:52
4. Jurgen Van den Broeck (Bel/Omega Pharma-Lotto) +2:13
5. Christophe Kern (Fra/Europcar) +2:52
6. Joaquim Rodriguez (Spa/Katusha) +3:01
7. Jean Christophe Peraud (Fra/AG2R) +3:30
8. Kanstantsin Siutsou (BLR/HTC-Highroad) +4:14
9. Janez Brajkovic (Slo/RadioShack) +4:22
10. Thomas Voeckler (Fra/Europcar) +4:27