Dani Pedrosa dominated the opening MotoGP practice session at Sepang, finishing comfortably clear of Honda team-mate Casey Stoner and championship rival Jorge Lorenzo.
The Spaniard, who captured pole for last year's abandoned race, was the first rider to dip into the 2m01s bracket.
With a quarter of the session to run he had worked his way down to a 2m01.621s, at the time putting him almost half a second clear of Stoner and Lorenzo.
It wasn't until the final two minutes that the pair were able to close that gap, although neither was able to really threaten Pedrosa's benchmark.
Stoner, in his second race weekend following his return from injury, came closest, eventually ending the session 0.152s down.
Lorenzo meanwhile clocked a 2m01.934s on his penultimate tour, just over three tenths down on his title rival.
While Stoner's form suggests he could be a factor in Sunday's race, Lorenzo can still clinch the title by simply finishing third in the remaining three races, regardless of what Pedrosa manages.
Fourth and fifth went to the Tech 3 Yamaha pair of Andrea Dovizioso and Cal Crutchlow, the Italian edging the intra-team battle by three hundredths of a second. Both riders finished more than six tenths down on Pedrosa however.
Ben Spies on the second works Yamaha claimed sixth ahead of LCR Honda's Stefan Bradl, the last rider to get within one second of Pedrosa.
Ducati's Nicky Hayden edged out Gresini Honda's Alvaro Bautista, third last weekend at Motegi, for eighth, while Pramac's Hector Barbera beat the second works Ducati of Valentino Rossi to 10th.
Rossi, winner of the last grand prix here in 2010, was more than 1.6s off the ultimate pace.