Imola - Jonathan Rea went unchallenged on his way to victory in Race 1 at the high-speed Imola circuit while Chaz Davies won a five-way fight for second.
Pata Honda's Rea, starting from pole position, made a very quick start off the line to lead through the first corner and by 0.7s at the end of the first lap.
Throughout the first half of the race his rivals were able to keep the gap down to under a second, however, a turn of speed from the Ulsterman coupled with those behind becoming locked into an intense battle for second, allowed Rea the freedom to eek out a lead.
Unchallenged on his way to the chequered flag, Rea secured the race win by 4.5s on board his Honda CBR1000RR.
Davies claimed second place while reigning World Champion Tom Sykes completed the podium ahead of his Kawasaki teammate Loris Baz.
Guintoli, who had fought back from a lap one mistake to run second with four laps to go, dropped to fifth ahead of Marco Melandri. The Aprilia rider had initially led the fight for second place before a mistake at Variante Alta dropped him down the order.
Eugene Laverty was seventh ahead of Alex Lowes, Toni Elias and Leon Haslam.
Leon Camier on board his BMW S1000 RR won the EVO class battle.
Davide Giugliano crashed out of the five-way battle for second with seven to go. The Ducati rider lost the front end of his Panigale and hit the dirt.
He was joined in retirement by Michel Fabrizio, Aaron Yates, Niccolo Canepa and Ayrton Badovini.