Newly crowned MotoGP world champion Marc Marquez led the timesheets on Tuesday as riders kicked off three days of testing in sizzling temperatures at Malaysia's Sepang circuit.
Honda's Marquez clocked 2 minutes 00.286 seconds for the day's top time, with Yamaha's nine-time Italian world champion Valentino Rossi just 0.518 seconds behind.
Marquez's teammate and fellow Spaniard Dani Pedrosa was third fastest, 0.62 seconds off the pace, with former world champ Jorge Lorenzo of Yamaha next.
Marquez and Rossi traded top times through the day as they blazed around a Sepang circuit that is notoriously tricky due in part to Malaysia's tropical moisture and frequent rain.
On Tuesday, the track was hot and dry, yielding fast times but leaving riders drained after the two-month layoff since last season.