Casey Stoner said he was far from comfortable with the feel of his Ducati during first practice for the Malaysian Grand Prix, despite lapping within a tenth of a second of pace-setter Jorge Lorenzo.
The Australian complained of a lack of grip from the rear of his bike, and chatter from his front tyre, but was happy with his pace.
"The lap times are surprisingly good considering the track conditions, which are definitely suffering from the heat and feel much less grippy than usual here," said the 2007 world champion.
"Having said that I didn't feel at all comfortable with the settings. Every time I went out there was a small problem holding us back - at first it was with the front chattering and folding, then we lost grip on the rear.
"There was no use staying out there on a bike that needed to be set up better so I had to keep coming in, which disrupted our rhythm and didn't give me chance to establish any kind of feeling."
Stoner, who missed three races during the middle of the year due to an illness, said that the hot and humid conditions at Sepang had not had an adverse effect on him.
"Even though it was hard work out there and I was tired by the end of the session, I don't think I was any worse off than anybody else," he added.
"And it is a different world compared to the way I felt at hot races earlier in the year. I'm happy with my physical condition."