Michael Rutter has taken his 27th career British Superbike Championship win after a measured performance in tricky conditions at Knockhill.

In a race that was heavily delayed and restarted twice, the Ridersmotorcycles.com Ducati kept his cool as the damp surface began to dry to pick off Josh Brookes and Ryuichi Kiyonari.

His first win in two years - when he triumphed on a Ducati in a similarly slippery conditions at Mallory Park -, it took two attempts to get the race going after a torrential downpour two laps into the first start forced a delay of almost 90 minutes.

The race was then stopped for a second time three laps into the restart when Dan Linfoot and Chris Walker came down at the opening bend, dragging mud across the circuit and requiring man power to clear the track.

The race eventually got underway definitively at the third time of asking with pole sitter Brookes sweeping into the lead ahead of Rutter and Kiyonari. With the circuit still predominantly wet from the earlier shower, Kiyonari worked his way to the front of the field, passing both riders to take the lead by lap six.

However, as the track began to establish a dry line, Rutter - the most experienced rider on the grid - began to make his presence felt, passing Brookes on lap eight before setting about on Kiyonari again.

Proceeding to follow for two laps, Rutter planted his move at the final corner chicane with five laps to go to nose into the lead.

Kiyonari attempted to respond, but his efforts would prove fruitless as Rutter kept it clean to complete a remarkable victory, a first for the Ridersmotorcycles.com team.

Kiyonari held on for second, ahead of Brookes, who despite fading has now assumed the lead of the BSB standings after Tommy Hill could only manage eighth.

Michael Laverty launched into a superb ride to finish fourth from his 20th position on the grid, just ahead of Relentless Suzuki team-mate Alastair Seeley and his brother John Laverty.

Kawasaki also enjoyed an encouraging race with Simon Andrews in seventh and Gary Mason being classified in an equal eighth with Hill after crossing the line together.

Walker completed the top ten after fighting his way back through the field, while AIM Suzuki's Gary Johnson held off his namesake David to claim Evo honours in a solid 12th position.

Despite the conditions, just three riders would retire, although Swan Honda endured a terrible race as Stuart Easton could only manage 19th, while James Ellison - who ran fourth early on - plummeted down the order to 24th.

The race two grid, meanwhile, will see Rutter start from pole, ahead of Kiyonari, Michael Laverty and Seeley.