Fabio Quartararo clocked the fastest practice time and set a new lap record at Sepang Friday ahead of the Malaysian MotoGP, a boost for the French rookie after he crashed out in Australia.
The 20-year-old Petronas Yamaha rider, whose race at Phillip Island last week ended at turn two when he collided with Danilo Petrucci, powered to a quickest lap of 1min 58.576sec in the afternoon session.
It was the second time he had broken the lap record -- previously held by Dani Pedrosa -- in the space of a day, after smashing it in the morning session.
Petronas Yamaha teammate Franco Morbidelli of Italy was second fastest, 0.534 behind the Frenchman.
Ducati's Andrea Dovizioso, this year's runner-up in the world standings and the winner at Sepang in 2016 and 17, was third fastest, 0.630 off the pace.
Already-crowned world champion Marc Marquez, aiming for his second consecutive victory in Malaysia on Sunday and his 12th of the season, only managed to clock the sixth fastest lap.
The Spaniard could cap a stellar season in Malaysia, the year's penultimate race, by sealing the team championship for Repsol Honda, to add to the riders' and constructors' accolades.
He also needs to score just nine points in Malaysia -- a seventh-placed finish or above -- to top three-time world champion Jorge Lorenzo's highest ever tally of 383 across 18 races.