Factory Honda rider Casey Stoner set the pace for his new team on the opening day of the first preseason MotoGP test at Sepang, having set a late flier to oust champion Jorge Lorenzo from the top of the times.
The Australian, riding a version of the 2010 RC212V and using a similar setup to the one he had tried at Valencia at the end of 2010, lapped the Malaysian Grand Prix venue in 2m01.574sec to outpace Lorenzo by 0.403sec.
"Very positive day." said Stoner. "At the beginning it took some time to get used to the bike again, but I soon felt comfortable and we had a good day.
"We didn't change the setup too much compared to the one we had in Valencia and I am pleased to see that even if the circuit is different, it still works pretty well here in Sepang. We did some work later on with the engine braking to decrease some chattering and it looks like we found a good solution.
"In the next two days we will start testing something new but anyway for me, it was a very good way to come back on track after the winter break."
Dani Pedrosa was third fastest on the second of the HRC Hondas, just 0.047sec off the pace of Lorenzo, while Marco Simoncelli was an impressive fourth fastest on the factory-supported Gresini Honda ahead of FIAT Yamaha new boy Ben Spies, who crashed in the morning without injury.
Alvaro Bautista was sixth fastest as he settled into life as Suzuki's sole representative in the premier class and expressed himself pleasantly surprised with the pace of the GSV-R - equipped with a new engine and chassis.
"It's been a long time since Valencia and, on my first laps, I thought Suzuki made a mistake and fitted a 1000cc engine in the bike, it feels so fast after a long break!" said the Spaniard, who back-to-back tested some new 2011 Ohlins forks. "But, after some easy laps, I began to get my rhythm and to ride comfortably.
"We did some interesting testing, but to be honest the main thing today was just for me to get back to a normal level and, in the end, the bike felt nice and we went quite quick, so I'm happy. I hope the weather stays dry, we have a big list of stuff to test and I know the guys will be working late tonight to prepare everything for tomorrow."
Hiroshi Aoyama was seventh quickest on the second Gresini bike, while Andrea Dovizioso was eighth fastest on the 2011 HRC bike. Colin Edwards and Randy de Puniet completed the top 10.
Valentino Rossi continued his adaptation to the 2011 Ducati GP11 and spent the day working on riding position. Still not at full strength from his shoulder surgery, the Italian tried a new shaped fuel tank to go 12th fastest.
British rookie Cal Crutchlow, who makes his MotoGP debut with Tech 3 Yamaha this year, was 16th fastest, some 2.5sec off the pace.
Pos Rider Team Time Gap
1. Casey Stoner Honda 2m01.574s
2. Jorge Lorenzo Yamaha 2m01.977s + 0.403s
3. Dani Pedrosa Honda 2m02.024s + 0.450s
4. Marco Simoncelli Gresini Honda 2m02.295s + 0.721s
5. Ben Spies Yamaha 2m02.332s + 0.758s
6. Alvaro Bautista Suzuki 2m02.422s + 0.848s
7. Hiroshi Aoyama Gresini Honda 2m02.483s + 0.909s
8. Andrea Dovizioso Honda 2m02.507s + 0.933s
9. Colin Edwards Tech 3 Yamaha 2m02.514s + 0.940s
10. Randy de Puniet Pramac Ducati 2m03.152s + 1.578s
11. Kousuke Akiyoshi Honda Test 2m03.224s + 1.650s
12. Valentino Rossi Ducati 2m03.365s + 1.791s
13. Nicky Hayden Ducati 2m03.508s + 1.934s
14. Loris Capirossi Pramac Ducati 2m03.695s + 2.121s
15. Hector Barbera Aspar Ducati 2m03.767s + 2.193s
16. Cal Crutchlow Tech 3 Yamaha 2m04.009s + 2.435s
17. Toni Elias LCR Honda 2m04.238s + 2.664s
18. Karel Abraham Cardion Ducati 2m04.470s + 2.896s