Andrea Dovizioso set the fastest lap time during a mixed Friday free practice session at Le Mans, during an hour long session split almost exactly in half by rain.
Friday's session was the first of the 2009 season to last for one hour, after a recent rule change reversed the switch to 'cost-cutting' 45-minute sessions.
However, the fast changing Le Mans weather did its best to negate the change, with rain arriving shortly after the midway point and sending all riders into the pits while bikes were adjusted to wet weather settings.
Most riders completed some wet laps during the last ten minutes, but conditions were tricky; the track was too wet for slicks but parts of the track had only a light sprinkling of rain.
Dovizioso had put his Repsol Honda on top of the timesheets just moments before the rain arrived and the change in conditions kept the young Italian in P1 by 0.058sec over Ducati's Casey Stoner.
Stoner, who dropped out of the podium fight at Le Mans last season after a technical problem late in the race, appeared to suffer some form of problem during the opening stages of Friday's session - the Australian sitting 18th and last, having completed five laps, after 20 minutes.
But the 2007 world champion got into his stride thereafter, moving up to seventh place on his sixth lap, then taking first position from home hero Randy de Puniet on his following circulation.
Stoner had described his Ducati as being difficult to muscle around the tight corners in previous seasons, but hoped the carbon-fibre GP9 - and electronic changes - would help in that regard.
de Puniet - now riding with Elf in place of the former Playboy logos on his LCR Honda - nevertheless remained in the top three until the arrival of the rain, with the Frenchman's best lap a mere 0.157sec behind Dovizioso.