James Toseland went a long way to suggest Yamaha has cured the set-up woes that afflicted its efforts during the opening round of the 2010 World Superbike Championship in Australia by snatching the fastest lap time during first free practice at Portimao.

Arriving in Portugal on the back foot after a troublesome - and bruising - weekend at Phillip Island, Toseland gradually scaled the timesheets before a series of quick laps during the final ten minutes lifted him ahead of erstwhile pace setter Leon Haslam.

One of the few circuits on the calendar that Toseland has never raced on previously, Toseland spent much of the session in the lower reaches of the top ten before pushing up to sixth, third and then second over three consecutive laps.

Eventually, a fourth and final push saw him post a 1min 44.351secs lap time, just under a tenth faster than championship leader Haslam.

Completing the British 1-2, Haslam got the ball rolling in the closing minutes of the session by going top with 13 minutes remaining, but only Toseland would overhaul him.

By the close of the hour, five different manufacturers filled the top five positions, with Honda's top representative coming in the form of Max Neukirchner, the German rider posting a big improvement to leap from 11th to third in the dying seconds. Max Biaggi and Jakub Smrz led the Aprilia and Ducati charge respectively.

Returning to the circuit where he made his World Superbike debut on five months ago, Sylvain Gunitoli was sixth fastest, ahead of Jonathan Rea, the Northern Irishman suffering a tumble mid-session but recovering to end up seventh.

Michel Fabrizio was consistently quick in the first sector but struggled to string a perfect lap together, leaving him eighth, ahead British pair Cal Crutchlow and Leon Camier.

Returning to the scene of his 2009 WSBK title heartbreak, Noriyuki Haga led the way early on but failed to improve on his initial efforts, forcing him to contend with 11th position.

Just behind, Phillip Island race winner Carlos Checa was a modest 12th, two positions up on team-mate Shane Byrne, the Althea pair being split by Troy Corser in the lead BMW entry.

Over at Kawasaki, Tom Sykes held down 15th position, but Chris Vermeulen would complete nothing more than two exploratory laps. The Australian says he intends to race this weekend, but has already admitted he is still recovering from injuries sustained in his crash at Phillip Island.

Of the newcomers, Makoto Tamada was 20th fastest on his Reitwagen BMW debut, while Sheridan Morais was 23rd on the Echo CRS Honda.