Foggy Petronas riders Troy Corser and James Haydon made progress throughout the first day of qualifying for the tenth round of the World Superbike championship at Assen, but the British ace continued to struggle to match his Aussie team-mate's performance.

On the team's first visit to the fast and flowing circuit, both riders had to learn the new back section of the circuit, in use for only the second year. Haydon is in his first full year of WSBK action, while Corser sat out 2002 while developing the FPR project.

The Australian shaved 1.5secs off his morning practice time to finish the afternoon session in 13th place, clocking a time of 2min 04.865secs to sit 2.262secs off the pace set by provisional polesitter Gregorio Lavilla.

"I was happy to get down into the fours by the end of the qualifying session," Corser admitted, "On my flying lap, I was trying to get a tow from Chili, but we came up behind a slower rider. Frankie got past him, I didn't, and he was away.

"I'm only now really starting to remember where the track goes, and the new section is a little bit tricky. Its first chicane is easy, but the long right and left section is very fast and I still need to find the right spot where to turn in.

"I have been playing with the rear shock and am still not 100 per cent happy with the setting yet. I have also changed the gearing and am still in between gears in some corners, although the changes have helped. The modifications to the engine seem to have got rid of a flat spot in the power curve. The front Michelin tyre feels pretty good, but the track was a little bit dirty, so I still have a few rears to try."

Haydon also improved his morning time by more than three seconds, recording a best lap of 2min 08.030secs, but still occupied 22nd spot.

"We have made steps forward and one particular rear made a big difference," the Briton insisted, "It was a real shame that the session was stopped for a red flag with just three minutes remaining, as I was on a hot lap on a qualifier. When I went back out there was too much traffic. I still need to change where I am riding the track slightly. You can take 1.5secs off your time with just tiny improvements at each corner here."