
The hot conditions didn't slow Valentino Rossi, with The Doctor topping the charts in the opening free practice.

The temperatures at Sepang crested triple digits as the
MotoGP paddock opened the action in Malaysia. Valentino Rossi topped the timesheets on Friday, followed by Repsol Honda’s Andrea Dovizioso and Rossi’s feuding teammate, Jorge Lorenzo.
Rossi’s pace was set in spite the unfavorable conditions, with the Sepang surface not just hot (near 130 degrees) but also dirty with grip an issue for many riders. The Doctor has not finished higher than third in a Grand Prix since his return from a broken leg, but will be keen on changing that stat on Sunday.
“It's been another good start for us here and we found a good setting straight away,” said Rossi. “I am feeling very comfortable on the bike and so far my shoulder is okay here. The track is quite dirty but that will get better and I love riding at this track, it's one of my favorites and I am always happy to be on the bike here.”
Dovizioso’s second-place continues the impressive form exhibited by the Italian at the recent Motegi round. Meanwhile, the future GP champ, Lorenzo, was less than two-tenths off Rossi’s pace as he seeks to snare his first career title in podium form.
"Today conditions were quite difficult, with the high temperatures and a dirty track,” said Lorenzo. “I'm happy though because I felt good on the bike, I rode fast and I was close to the first position.”
Heading the provisional second row is Ducati’s Casey Stoner. Winner of the last two Grand Prix, the Australian managed a fourth-fastest pace in spite of a low-side crash early in the free practice session.
“I'm not really happy with the way things went today,” said the 2007 champ. “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.”

Jorge Lorenzo maintained a third-fastest pace as the Yamaha ace looks to wrap up his maiden GP title.
Stoner was followed by an unfamiliar name in the top-five this season, Suzuki’s Alvaro Bautista. The Spanish rider made his charge on the GSV-R, which has struggled all season long, but came alive in the Sepang heat. Also charging into the provisional second row is American Colin Edwards, continuing his impressive form after his fifth-place finish at Motegi, his best result of the season.
The World Superbike Yamaha-bound Marco Melandri paced seventh-fastest in the opening session. Supermarco was followed by Ducati satellite rider Aleix Expargaro and Yamaha’s Ben Spies. The American was well off the pace of Rossi, whose seat he will take over on the factory Yamaha squad next season.
As for fellow countryman Nicky Hayden, the Kentucky Kid had a woeful beginning to his Sepang effort. The former GP champ was well off the pace, more than 1.2 seconds adrift of the man he beat for the 2006 title.
Said Hayden: “We have picked up where we left off in Japan, which is not a good thing. 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.”

Ducati's Casey Stoner managed a fourth-fastest result in opening practice at Sepang, with the Aussie chasing his third consecutive victory on Sunday.
2010 MotoGP Sepang Practice Results:
1. Valentino Rossi (Yamaha) 2'02.724
2. Andrea Dovizioso (Honda) 2'02.833
3. Jorge Lorenzo (Yamaha) 2'02.898
4. Casey Stoner (Ducati) 2'03.160
5. Alvaro Bautista (Suzuki) 2'03.338
6. Colin Edwards (Yamaha) 2'03.393
7. Marco Melandri (Honda) 2'03.438
8. Aleix Espargaro (Ducati) 2'03.471
9. Ben Spies (Yamaha) 2'03.477
10. Randy de Puniet (Honda) 2'03.539
11. Marco Simoncelli (Honda) 2'03.680
12. Loris Capirossi (Suzuki) 2'03.717
13. Hector Barbera (Ducati) 2'03.760
14. Hiroshi Aoyama (Honda) 2'03.769
15. Nicky Hayden (Ducati) 2'03.947
16. Mika Kallio (Ducati) 2'04.023