Vinokourov showed his climbing prowess on Thursday

Spaniard Jose Angel Gomez, riding for Saunier Duval, was second with Belgian Davitamon rider Wim Van Huffel third and Lance Armstrong in fourth.

The stage was a 187-km (116-mile) ride which ended at the top of the infamous Mont Ventoux climb.

Gerolsteiner rider Levi Leipheimer retained the overall leader's jersey ahead of fellow American Armstrong.

Armstrong, who will be aiming to win the Tour de France for the seventh time next month, trails Leiphemer by 21 seconds.

After the race Armstrong warned he would be ready to win his seventh successive Tour de France next month.

"You often see riders do well in the Dauphine Libere and a month later they are not so strong," he said. "I have learnt not to be impatient. It was difficult today but the real test is a month away and I stay on schedule.

"I'm trying to gain some condition here, some race rhythm and to focus on the big objective.

"Everybody is calm and collected and we are ready," he said.

Results from stage four of the Dauphine Libere (Tournon-sur-Rhone to Mont Ventoux)

1. Alexandre Vinokourov (Kazakhstan/T-Mobile) 4 hours, 7 minutes, 23 seconds
2. Jose Gomez Marchante (Spain/Saunier Duval) 6 seconds behind
3. Wim Van Huffel (Belgium/Davitamon-Lotto) :16
4. Lance Armstrong (US/Discovery Channel) :37
5. Floyd Landis (US/Phonak) :41
6. Andrey Kashechkin (Kazakhstan/Credit Agricole) :43
7. Levi Leipheimer (US/Gerolsteiner) :46
8. Inigo Landaluze (Spain/Euskaltel-Euskadi) 1:31
9. Nicolas Fritsch (France/Saunier Duval) 1:36
10. David Moncoutie (France/Cofidis) 1:45

Overall standings in Dauphine Libere (after stage four)

1. Levi Leipheimer (US/Gerolsteiner) 15:19:29"
2. Lance Armstrong (US/Discovery Channel) +21"
3. Alexandre Vinokourov (Kazakhstan /T-Mobile) +26"
4. Floyd Landis (US/Phonak) +37"
5. Andrey Kashechkin (Kazakhstan/Credit Agricole) +2:00"
6. Santiago Botero (Colombia/Phonak) +2:25"
7. Jose Angel Gomez (Spain/Saunier Duval) +2:53"
8. Marzio Bruseghin (Italy/Fassa Bortolo) +3:07"
9. Oscar Pereiro (Spain/Phonak) +3:16"
10. David Moncoutie (France/Cofidis) +3:45"