Byrne, who had topped qualifying on Saturday, blitzed the field in the opening race, leading from lights to flag to beat Josh Brookes into second place.
And in the second race he pulled off the exact same feat, with Brookes again second.
Byrne's lead in the BSB championship standings is now up to 17 points over Brookes, with James Ellison 33 points off the pace in third.
While there was little racing drama at the head of the field, with Byrne almost three seconds clear in the first race and five seconds in the second race, there was an extraordinary moment in race two as Taylor Mackenzie's Team WD-40 Kawasaki caught fire as he rode.
At first Mackenzie didn't even notice - but as the flames began to lick up in between his legs he quickly pulled off the track and ran for safety.
