Filippo Ganna of Ineos won the fourth stage of the Etoile de Besseges after shaking off the other survivors of a long breakaway in the final kilometres on Saturday.
The 24-year-old Italian was part of a small group that escaped early in the 151.6 kilometre ride from Rousson to Saint-Siffret, north-east of Avignon.
The five-day race is the first of the season on the UCI calendar and has attracted a strong field including Ganna's Tour de France-winning team-mates Egan Bernal and Geraint Thomas.
Ganna, the world time-trial champion, powered away from the other six breakaway members on a gentle slope. Despite an energetic pursuit, Ganna held on to win by 17 seconds. He was followed home by Frenchman Christophe Laporte (Cofidis) and German Pascal Ackermann (Bora).
Belgian Tim Wellens of Lotto-Soudal kept his 44-second lead over compatriot Edward Theuns of Trek-Segafredo in the overall classification.
The race finishes on Sunday with an 11km time-trial in Ales.