The Spaniard started eighth and ran in the same position in the early stages, before gradually picking his way through the order to catch Rea. Signalling his third podium of the season, it comes at a crucial time when Checa is believed to be fighting for his place in the team.
Rea settled for fourth, more than five seconds ahead of Biaggi, who came away with fifth after a race-long battle with Corser, Haslam and Fabrizio. Corser had held fourth for much of the time, but began to fade as the race progressed, slipping into the clutches of his rivals and eventually finishing in eighth position.
As such, Haslam was able to benefit, finishing a solid sixth having fallen from third to eighth at the start on the Stiggy Honda, while Fabrizio was a quiet seventh as he watches his slim title hopes slide away.
Unable to replicate the pace of his team-mate, Tom Sykes was a lonely ninth on the second Yamaha, while fellow Briton Shane Byrne completed the top ten.
Outside the top ten, Matthieu Lagrive, Karl Muggeridge, Jakub Smrz, Ryuichi Kiyonari and Yukio Kagayama were the remaining point scorers. Briton Richard Cooper, meanwhile, crashed out of 15th position, seven laps into the race.