Jorge Lorenzo was quickest in Saturday morning practice for the Japanese Grand Prix at Motegi, beating Andrea Dovizioso and Valentino Rossi by just under half a second.
With title rival Dani Pedrosa already back in Spain for surgery on the injuries he received yesterday, Yamaha rider Lorenzo could virtually secure the championship this weekend - though he will be unable to celebrate until it is clear when Pedrosa will return.
Lorenzo set the pace this morning with a lap of 1m47.413s, which took him ahad of his team-mate Rossi halfway through the session. Dovizioso - now Honda's only hope for victory at its home race - then pushed Rossi back to third a few moments later.
Aragon winner Casey Stoner had led the way initially on his Ducati, but did not improve on his early 1m48.059s and ended up fourth.
The under-pressure Suzuki team looks set for a morale boosting weekend. Loris Capirossi and Alvaro Bautista filled the final top six places for much of the hour, although Tech 3 Yamaha's Colin Edwards split them late on.
Marco Simoncelli was eighth for Gresini Honda, followed by Ben Spies on the second Tech 3 bike and Nick Hayden on the second works Ducati.
Home rider Hiroshi Aoyama (Interwetten Honda) could not repeat his excellent Friday form and was only 13th.
The session took place in dry and sunny conditions, and saw little incident, with Randy de Puniet's trek through the hairpin gravel on his LCR Honda the only error of note.
Pos Rider Team Time Gap
1. Jorge Lorenzo Yamaha 1m47.413s
2. Andrea Dovizioso Honda 1m47.836s + 0.423s
3. Valentino Rossi Yamaha 1m47.905s + 0.492s
4. Casey Stoner Ducati 1m48.059s + 0.646s
5. Loris Capirossi Suzuki 1m48.349s + 0.936s
6. Colin Edwards Tech 3 Yamaha 1m48.409s + 0.996s
7. Alvaro Bautista Suzuki 1m48.508s + 1.095s
8. Marco Simoncelli Gresini Honda 1m48.629s + 1.216s
9. Ben Spies Tech 3 Yamaha 1m48.643s + 1.230s
10. Nicky Hayden Ducati 1m48.669s + 1.256s
11. Aleix Espargaro Pramac Ducati 1m48.921s + 1.508s
12. Randy de Puniet LCR Honda 1m48.958s + 1.545s
13. Hiroshi Aoyama Interwetten Honda 1m48.973s + 1.560s
14. Marco Melandri Gresini Honda 1m48.978s + 1.565s
15. Hector Barbera Aspar Ducati 1m49.441s + 2.028s
16. Mika Kallio Pramac Ducati 1m49.826s + 2.413s