Tyco Suzuki's Alastair Seeley topped the first free practice session at Snetterton, scene of the fourth round of the MCE British Superbike Championship in Norfolk.
Seeley headed a one-two for Northern Ireland with Ian Lowry posting the second quickest time in FP1 on the Padgetts Honda CBR1000RR, with Shane Byrne on the Rapid Solicitors Kawasaki in third, just 0.009s behind Ulsterman Lowry.
Current British Supersport champion Seeley, fresh from a hat-trick of victories at the North West 200 road races last weekend, was the only rider to register to dip under the 1m 50s barrier with a time of 1m 49.819s giving him the top time by just 0.183s from Lowry.
Only half a second split the leading five, with one second covering the top ten riders in the opening session.
Graeme Gowland on the WFR Honda and team-mate Alex Lowes, plus Samsung Honda's Michael Laverty, Lowry's team-mate Lucan Scassa and Patric Muff on the Supersonic BMW were the top eight.
Lowes and fellow WFR Honda team-mate James Westmoreland both crashed during the session, but escaped unhurt.
Swan Yamaha's Tommy Hill and Oulton Park hero Chris Walker completed the top ten.
Seeley's Tyco Suzuki team-mate Josh Brookes was 11th fastest, with Noriyuki Haga 14th on the second Swan Yamaha YZF-R1.
Michael Rutter on the MSS Bathams Kawasaki was 18th fastest and Stuart Easton (Rapid Solicitors Kawasaki) 20th.
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