Casey Stoner, will be fighting for his third MotoGP victory in a row on Sunday in Malaysia, led the opening laps of Friday practice at Sepang - but then suffered a small fall from his Desmosedici.
The Australian returned on his spare bike, but lost out to Valentino Rossi (Yamaha), Andrea Dovizioso (Honda) and Jorge Lorenzo (Yamaha) to finish the session in fourth place.
“I'm not really happy with the way things went today," said Stoner, winner in the wet at Sepang last year. "We had a small crash at the beginning of the session so had to switch bikes and do a lot of work to get it feeling better.
"Every time I went out there was some small problem and we seemed to take a while to find a reasonable setting. By the end I had established a good feeling and I wanted to make a better lap time on the second lap of my final run but I ran wide in turn one and that was that.
"We'll take this data and try to improve the bike for tomorrow. We seem to be struggling most of all with the rear, just like at Motegi, but once we solve that I'm sure we'll see major improvements with the rest of the bike.”
If Stoner thought he had problems, he should spare a thought for team-mate Nicky Hayden, who was just 15th fastest out of the reduced 16 rider field.
The only good news for Hayden, who had a tough weekend at Motegi, is that he was 'only' 0.8 seconds slower than his team-mate, around the second longest circuit on the calendar.
“We have picked up where we left off in Japan, which is not a good thing," Hayden admitted. "We struggled a lot, right from the beginning, over the bumps mainly. I have a lot of front chatter, we got rear chatter too, and I cannot carry any good corner speed.
"We're 1.2 seconds off the top, which may not seem that much but the reality is that it is a lot when the field is as tight as it is right now. That kind of gap is pretty much going to send you to the back. We definitely need to do something for tomorrow because today was not good.”