Ducati's Andrea Dovizioso topped the opening free practice session of the 2018 MotoGP season in Qatar ahead of Yamaha's Valentino Rossi.
Dovizioso's teammate Jorge Lorenzo – who spent the opening session evaluating his GP18 without the aerodynamic fairing he used to great effect last season – was the early pacesetter with a 1:56.845s.
Rossi – who signed a two-year contract extension with Yamaha on Thursday – deposed him just moments later, though the Ducati rider soon struck back with a 1:56.439s. About a minute later, reigning world champion Marc Marquez took over top spot.
With 20 minutes to go, '17 runner-up Andrea Dovizioso shot to the top of the timesheets with a 1:55.806s, which stood as the benchmark through to the final five minutes.
Rossi, evaluating his M1 with and without the aero fairing, moved ahead of Dovizioso with a 1:55.723s, though the Ducati man made sure this was short lived by streaking clear with a 1:55.366s about a minute later.
A final effort from Rossi put him to within 0.061 seconds of Dovizioso into second spot, with Marquez completing the top three on his Honda.
Suzuki's Andrea Iannone leaped up to fourth on his final attempt ahead of Lorenzo, while Tech3 Yamaha's Johann Zarco opened up his sophomore premier class campaign sixth quickest at the end of FP1.
LCR Honda's Cal Crutchlow headed the sister Suzuki of Alex Rins, while Danillo Petrucci headed Ducati stablemate Tito Rabat in ninth.
Last year's Qatar race winner Maverick Vinales endured a fairly low-key first session at Losail, the Spaniard 11th ahead of a similarly under-the-radar Dani Pedrosa.
Aleix Espargaro was 13th as he tried the long-awaited new Aprilia engine, with late faller Alvaro Bautista and Tech3 rookie Hafizh Syahrin rounding out the top 15.
Syahrin's fellow rookie Tom Luthi [20th] was the first crasher of the season, the Marc VDS rider coming off at the first corner in the opening minute. KTM's Pol Espargaro also took a trip through the Losail gravel traps at Turn 4, but walked away unscathed.
