Rapax driver Coletti made a fine start from third on the grid, outdragging front row man Rene Binder to chase polesitter Adrian Quaife-Hobbs on the opening lap.
Coletti pounced for the lead on lap three at the Nouvelle Chicane, pulling a sublime outbraking move down the inside of Quaife-Hobbs' MP Motorsport car.
Coletti pulled out a two-second lead, but this then fluctuated as the leader managed his tyres, which appeared to grain as the race progressed. It came down to as little as seven tenths of a second at one point, but was back out to 1.8s by the finish.
Quaife-Hobbs just held on to second despite a late charge from GP3 champion Mitch Evans), who had passed James Calado at Mirabeau in a tight move for third on the opening lap.
Felipe Nasr also passed Calado, the latter cutting the apex at Ste Devote and being forced to give his place up.
Behind the top five, Binder clung to sixth after his slow start.
Friday's winner Sam Bird ran seventh early on, but his tyres wilted badly after Kevin Ceccon passed him at the chicane and he was forced to pit for fresh rubber.
Stephane Richelmi made it two Monagasque drivers in the points-paying positions with eighth.
- Sports & Recreation
- Rene Binder