Tommy Hill led a Swan Yamaha 1-2 in first free practice as the fifth round of the MCE British Superbike Championship got underway in rainy conditions at Knockhill.
Hill, who is on the comeback trail having spent the last two BSB events suffering with the shoulder injury he sustained at Oulton Park, swept to the top of the timesheets in the closing seconds at the expense of team-mate and Thruxton race winner Michael Laverty.
Championship leader Shane Byrne had held the top spot for a lengthy period, but would be demoted to third position, just ahead of closest rival in the standings, John Hopkins.
Half a second back, James Westmoreland leapt up to fifth in the final stages aboard the Motorpoint Yamaha, ahead of the top EVO rider Glen Richards, the Australian back on a Superbike at the circuit where he broke his leg two years ago.
Westmoreland's team-mate Loris Baz followed in seventh, ahead of Jon Kirkham and newly-confirmed full-time MSS Colchester Kawasaki rider Alex Lowes. Reigning champion Ryuichi Kiyonari completed the top ten.
The two American newcomers – WFR Honda's Jake Zemke and Splitlath Aprilia's Mark Miller – were 31st and 34th respectively.