Chaz Davies (Aruba.it Racing – Ducati) crashed out of a safe second place near the end, losing the front, but by then Rea had already eased his way to what became his 11th win of the season.
His fellow podium placers proved to be first time Yamaha top three rider Michael van der Mark (Pata Yamaha Official WorldSBK Team) in second, with Marco Melandri (Aruba.it Racing – Ducati) scoring his second podium place of the weekend in third.
Rea took only two laps to get to the front of the race, from ninth, with early leader Leon Camier (MV Agusta Reparto Corse) picked off by faster machines after leading the first lap.
Eugene Laverty (Milwaukee Aprilia) held off Davies early in the race but succumbed to first the Welshman early on and then van der Mark later.
Laverty and Melandri had a fight later in the race after Davies and Rea were long gone out front.
A promising ride from Camier came to nothing despite his pole position start under the reshuffled race two grid rules. He experienced a technical issue on his machine and he retired.
With Laverty fourth, Jordi Torres (Althea BMW Racing Team) piled in with a fifth place, and Lorenzo Savadori (Milwaukee Aprilia) a sixth.
Leandro Mercado (IodaRacing Team Aprilia) was seventh and returnee WorldSBK rider Anthony West (Kawasaki Puccetti Racing) a clear eighth.
Ayrton Badovini (Grillini Racing Team Kawasaki) was ninth and Takumi Takahashi (Red Bull Honda World Superbike Team) tenth.
Stefan Bradl (Red Bull Honda World Superbike Team) did not start the race after hurting his wrist during his Saturday race crash, and Tom Sykes (Kawasaki Racing Team) was of course out after undergoing surgery on his injured left hand in Spain today.
Alex Lowes (Pata Yamaha Official WorldSBK Team) crashed out of race two and no-scored
In the championship Rea has 431 points, Sykes 311, and Davies 296.
By Gordon Ritchie