Rossi is gearing up to chase his sixth MotoGP crown this year

The five-time world champion smashed the old best mark with a time of one minute 38.394 seconds on his Yamaha.

The new time was set despite the fact that this year's bikes in the MotoGP class have been reduced in capacity from 990cc to 800cc.

The previous best lap was 1:39.064 set by Loris Capirossi on a Ducati in 2006.

"It's magnificent, but of course it doesn't count towards world championship points," Rossi said. "It is the first battle won.

"The new Yamaha is already faster than last year's model and it seems to be effective at every circuit. It is a good starting point for 2007."

Rossi lost his crown when he finished as runner-up behind Nicky Hayden in last year's championship.

Title rival Dani Pedrosa of Spain was second quickest on Sunday, 0.133 down on the Yamaha rider.

Rossi's team-mate Colin Edwards clocked the third fastest time, while Hayden was fourth quickest.

The season-opening Grand Prix takes place in Qatar on 10 March.