The Fortuna Aprilia rider, who can afford to lose 20 points to Honda's Andrea Dovizioso in Sunday's race and still be crowned one round early, was fastest for much of the session - before being briefly dropped to fourth in the closing stages.

The 2008 Fiat Yamaha MotoGP rider bounced back with two minutes to go, initially breaking half a second clear of the field before that margin was reduced to just 0.092secs by Dovi by the chequered flag.

Alvaro Bautista was third fastest with Swiss rider Thomas Luthi completing a provisional front row containing two Aprilias and two Hondas. Mika Kallio was fifth for KTM with Marco Simoncelli the lead Gilera in sixth.

First qualifying - Sepang:

1. Lorenzo (Aprilia)

2. Dovizioso (Honda) +0.092secs

3. Bautista (Aprilia) +0.279secs

4. Luthi (Aprilia) +0.511secs

5. Kallio (KTM) +0.771secs

6. Simoncelli (Gilera) +0.856secs

7. H. Aoyama (KTM) +1.212secs

8. Locatelli (Gilera) +1.633secs

9. Simon (Honda) +1.652secs

10. Barbera (Aprilia) +1.820secs

20. Laverty (Honda) +3.771secs