Casey Stoner was fastest in the opening free practice session for MotoGP's first American date of the year at Laguna Seca.
A 1m22.300s early in the morning was sufficient to keep championship leader Stoner on top for the rest of the session.
His Honda team-mate Dani Pedrosa followed up his Sachsenring win with second this morning, moving to within 0.102 seconds of Stoner with his final lap. Pedrosa was the only man to crash in the session, having a very minor fall when he went into the gravel at Turn 2.
That last-gasp run by Pedrosa demoted Jorge Lorenzo's Yamaha to third, ahead of team-mate Ben Spies - the top home rider - and the third Honda of Andrea Dovizioso, with Marco Simoncelli (Gresini Honda) sixth.
Nicky Hayden led Ducati's charge again in seventh, having tried both the GP11 and 2012-chassis-based GP11.1 - but lapped quicker on the original bike. Valentino Rossi stuck with the latter and was ninth, ahead of Colin Edwards' Tech 3 Yamaha.
AMA Superbike rider Ben Bostrom was unsurprisingly slowest as he got to grips with MotoGP on his one-off appearance with LCR Honda. Bostrom's best time was 4.986s off Stoner's pace and 1.961s behind nearest rival Hiroshi Aoyama (Gresini).
Pos Rider Team/Bike Time Gap
1. Casey Stoner Honda 1m22.300s
2. Dani Pedrosa Honda 1m22.402s + 0.102s
3. Jorge Lorenzo Yamaha 1m22.420s + 0.120s
4. Ben Spies Yamaha 1m22.806s + 0.506s
5. Andrea Dovizioso Honda 1m22.911s + 0.611s
6. Marco Simoncelli Gresini Honda 1m23.210s + 0.910s
7. Nicky Hayden Ducati 1m23.297s + 0.997s
8. Colin Edwards Tech 3 Yamaha 1m23.459s + 1.159s
9. Valentino Rossi Ducati 1m23.467s + 1.167s
10. Alvaro Bautista Suzuki 1m23.529s + 1.229s
11. Hector Barbera Aspar Ducati 1m23.596s + 1.296s
12. Randy de Puniet Pramac Ducati 1m23.807s + 1.507s
13. Cal Crutchlow Tech 3 Yamaha 1m24.018s + 1.718s
14. Toni Elias LCR Honda 1m24.324s + 2.024s
15. Loris Capirossi Pramac Ducati 1m24.566s + 2.266s
16. Karel Abraham Cardion Ducati 1m24.682s + 2.382s
17. Hiroshi Aoyama Gresini Honda 1m25.325s + 3.025s
18. Ben Bostrom LCR Honda 1m27.286s + 4.986s