After leading all six track sessions at the Qatar season opener, Casey Stoner lost P1 to Valentino Rossi by just 0.056sec at the end of Friday practice for the Japanese Grand Prix at Motegi.

Nevertheless, the Ducati Marlboro star believes the single 45-minute session - held in cool conditions - went "as well as we could have expected" and is now waiting to see what the weather will do, with rain predicted for Saturday.

"We're not too far from setting some very decent lap times and considering how cold it was this afternoon I think everything has gone as well as we could have expected," said the Australian.

"It looks as though the weather forecast is not good for tomorrow so this session might not turn out to be so important in terms of qualifying, but then if it's dry again on Sunday it could turn out to be crucial.

"In general the bike feels quite good - we need to try and find a bit more grip on the rear and we have a few ideas that we think could work - but now it's just a case of seeing what the heavens throw at us tomorrow and dealing with that as best we can."

Team-mate Nicky Hayden, who headed into the action with the stitches he had inserted into his chest after a huge Qatar qualifying fall, shrugged off the discomfort to turn in a 'satisfying' afternoon's work.

However, the American was only ranked twelfth fastest, 1.848sec from Rossi.

"The track was quite slippery when we first went out and the air felt so cold, with the humidity, it felt like it could rain any second. We certainly had to be careful getting some heat into the left side of the rear and into the front," said Nicky.

"We tried a few things out with the set-up - I ran both bikes and worked in the direction we'd found in Qatar, where the balance of the bike had felt much better in the later laps, with less fuel on board.

"Obviously the lap time isn't great but we improved with every run and pretty much every lap, we got a good number laps in just in case it does rain tomorrow and we worked out a basic direction we need to take for the race, so I'm satisfied."