With a poor start consigning him to the chasing pack in race one, Guintoli was making swift amends on this occasion, dispatching Vermeulen at the start of lap two before pulling off a stunning pass on both Haga and Fabrizio through turns one and two on lap three.
A sight not seen in World Superbikes for some time, Suzuki were now in a provisional 1-2, but any expectations that Guintoli would simply shadow his team-mate were dismissed on lap six when he snatched the lead from Haslam down the home straight.
Checa, meanwhile, continued to make progress, picking off Camier for sixth and Toseland for fifth by lap eight. Even so, he was still left with a deficit to make up on the top four, which had now pulled out a two second gap to the chasing pack that he now led.
Checa's cause, however, was aided by the scrapping up front, with Guintoli and Haslam battling away for the lead, the pair swapping positions on a number of occasions while Fabrizio and Haga kept a close watching brief in third and fourth.
Guintoli's hopes of a first World Superbike win appeared to improve on lap sixteen when an aggressive move for the lead saw Haslam drift wide and allow Fabrizio between them. However, Haslam composed himself to resume second position just a lap later before proceeding to move back past Guintoli at Honda with three laps remaining.
During this time Checa had worked his way into the lead group, the former MotoGP rider signalling his intent by dismissing Haga for fourth almost straight away. Shadowing Haslam's pass on Guintoli, Checa went on to move into third ahead of Fabrizio to assume the Ducati challenge.
As Guintoli began to fade, Checa was quickly up to second with a neat pass at MG, leaving just Haslam between himself and victory as they entered the final lap.
Having rebuffed Fabrizio's last lap attentions during race one, Haslam looked confident as he held off Checa's first overtaking attempt through Honda. However, the charging Spaniard would not be denied, launching a second attack over Lukey Heights and down into MG, Checa forcing the bike up the inside of the Haslam and hanging him out long enough to prevent a response through the ensuing left-hander.
Breaking any potential tow as he exited the last bend, Checa crossed the line to jubilation from his stunned Althea team. Indeed, Checa himself was visibly emotional when he stepped off the bike as his first win since Miller Motorsports Park in 2008 sunk in.
Haslam was a philosophical second, while Fabrizio secured the final podium position at the expense of Guintoli, whose feisty performance was rewarded with a fine fourth place finish and the fastest lap of the race. Haga, meanwhile, slipped back to finish almost four seconds adrift in fifth.