Leon Haslam continued to stamp his authority on proceedings as the first day of World Superbike testing drew to a close in Portugal, the Suzuki rider's performance highlighting a hugely successful opener for the British contingent.

Having topped the timesheets in the morning, Haslam came out fighting again in the afternoon and was soon under the 1min 43secs marker before ending his day with a best time of 1min 42.778secs.

Now within three tenths of the lap record, Haslam this time had Cal Crutchlow to fend off, the rookie Yamaha rider doing a fine job of climbing his way into second position as the only other man to join Haslam in the 1min 42secs bracket.

In all, five British riders filled the top six spots, with Jonathan Rea proving third fastest, despite hurting his finger in an earlier accident, while James Toseland and Shane Byrne joined their compatriots in the upper echelons by going fifth and sixth.

Only Max Biaggi could upset the 'national order', the Aprilia rider ending the day fourth best despite being the only rider not to improve on his earlier lap time.

Despite Haslam's improvements, the lap times during the afternoon session were closer, with just over a second covering the top ten. Noriyuki Haga and Michel Fabrizio were once again barely separated in seventh and eighth, although with Byrne sixth and Carlos Checa ninth, the factory Ducati riders will be slightly bemused to see the new satellite Althea team straight on the pace.

Leon Camier completed the top ten, marginally ahead of former BSB rival Sylvain Guintoli, while Tom Sykes was a substantial improver between sessions to leapfrog BMW and go 12th best for Kawasaki.

Troy Corser was 13th fastest as he brought Davide Tardozzi's first day as BMW team manager to an unspectacular close, while Max Neukirchner and Chris Vermeulen posted marginal improvements in 14th and 16th.