Haga held on for sixth, just keeping Alastair Seeley at bay, while Graeme Gowland, Alex Lowes and Michael Rutter crossed the line in tandem to complete the top ten.
James Westmoreland finished 11th, but only after losing time with an off at the final corner hairpin, the WFR Honda rider clawing back ground to beat Jon Kirkham, Tristan Palmer, Luke Quigley and Patric Muff.
Elsewhere, Chris Walker's heroic efforts came to an unsatisfactory end on lap nine when his Pr1mo Bournemouth Kawasaki developed technical issues, while Peter Hickman's first race for Buildbase BMW would also end prematurely, albeit in the gravel.
In the overall standings, Hill has moved ahead of Brookes, while Byrne has closed up the gap to the top two in third place and Laverty has moved clear of Lowry in fourth.
The grid for race two will see Hill on pole position once again, ahead of Byrne and Laverty, while Lowry, Westmoreland and Haga make up row two. Brookes, meanwhile, paid for his laboured pace by only securing a time good enough for ninth.