Click here for full BSB FP1 results from Oulton Park
Josh Brookes has started quickest at Oulton Park after pinching top spot from Shane Byrne with his final flying lap in FP1.
The PBM Kawasaki rider had been comfortably ahead of the field for the majority of the morning session and looked assured of P1 until the MCE British Superbike championship leader picked up where he left off having won the last six consecutive races.
As the chequered flag was readied to end FP1, Brookes stole top spot from Byrne with his final flyer, a 1m 35.556s, edging the defending champion out by just 0.023s.
Tommy Bridewell, a winner at Oulton Park in May, grabbed third on the timesheet from Danny Buchan in the closing stages as Luke Mossey rounded out the top five.
Christian Iddon continued to make strong progress on the Bennetts Suzuki in sixth while Chris Walker, who will celebrate his 300th British Superbike race on Saturday, proved he was still 'old but gold' by topping the timesheet in the opening stages before being displaced down to seventh.
Double rostrum winner at Cadwell Park Peter Hickman grabbed eighth as Jack Kennedy and Billy McConnell rounded out the top ten.
As FP1 went green the Oulton Park track had been slowly drying out after overnight rain as the majority of riders eased into the race weekend.
After struggling to match the pace of the front-runners over the past few rounds Byrne appeared to find a solution to his recent problems with the PBM Kawasaki ZX-10R as he pulled out a three-tenths advantage on Brookes, but it was the Milwaukee Yamaha rider who stole top spot at the death.
Injured duo James Ellison and Stuart Easton made solid comebacks in 12th and 13th respectively while Showdown contender Michael Laverty started the weekend slightly off the pace in 18th.
It was a frustrating start to the weekend for Buildbase BMW's Ryuichi Kiyonari who failed to set a lap time. The three-time BSB champion was only able to complete an out lap before returning to the pits with a technical problem.