He made his first move, on team-mate Camier, on lap twelve before passing Ellison almost immediately after when the Hydrex Bike Animal rider made a mistake at the Esses to allow both Airwaves Ducatis through.
With Harris and Crutchlow beginning to struggle with tyre wear, as well as the buffeting winds sweeping across the circuit, Byrne slipped up the inside of Crutchlow at Melbourne Hairpin on lap 17 and set about attempting to wrestle the win off long time leader Haslam.
He didn't have to wait long, Byrne mirroring Haslam throughout lap 18 before pulling an identical manoeuvre at Melbourne to sneak into the lead. Once ahead, Byrne simply eased to a comfortable advantage to secure a sixth victory of the season and in the process extend his championship lead to 68 points.
Haslam scored his second podium of the day, ahead of Crutchlow, who held off a charging Camier in the closing stages to take third on the track and, with it, second in the standings.
Ellison dropped back rapidly after slipping to fifth but still finished three seconds up on Tom Sykes, who couldn't match his podium from the first race, even if he still made up seven places in the race.
Harris, who pressured Byrne in the early stages, had to settle for an anonymous seventh, while Rutter was another to fall out of contention following a quick start to cross the line in eighth. Simon Andrews claimed his second top ten finish of the day in ninth, while Guy Mason scored a best result of the season for Cup rider in tenth.
