Swan Yamaha's Tommy Hill became the first rider this season to win two races with a polished ride to victory in race one at Snetterton.
The reigning MCE British Superbike champion stretched his advantage in the championship table to 15 points over Tyco Suzuki's Josh Brookes after beating Samsung Honda's Michael Laverty by 1.234 seconds after 16 laps, with Aussie Brookes claiming the final spot on the rostrum.
Noriyuki Haga out-dragged WFR Honda's Alex Lowes in a sprint finish to the line to snatch fourth from the 22-year-old's grasp, while Tommy Bridewell put in an impressive performance on the Supersonic BMW to take fifth.
Veteran Chris Walker and Ulsterman Ian Lowry on the Padgett's Honda were locked in battle for sixth place on the final lap, with Walker narrowly holding on by a whisker at the finish line as Lowry attempted to power past.
It was a miserable opening race for Paul Bird's Rapid Solicitors Kawasaki team, with Stuart Easton retiring with an electrical fault and Shane Byrne also being forced out of the race while holding fourth position on lap six.
Laverty, who had struggled to live up to the promise he showed during pre-season testing prior to his podium finish at the Snetterton 300 circuit in Norfolk, led the race in the opening stages.
He briefly lost the lead on lap six when Brookes and Hill both passed the Samsung Honda rider before running wide, allowing the Northern Irishman back into the lead.
However, Laverty was coming under increasing pressure from Hill, who forged his way past Brookes on the seventh lap.
The Swan Yamaha man soon took over at the head of affairs after making his move at Agostini's, with Lowes into fourth place after putting a pass on Haga.
Brookes edged past Laverty at the end of the start/finish straight on lap eight and almost took out Hill as he attempted a pass on the brakes, running wide and allowing Laverty back into second.