Defending MotoGP world champion Marc Marquez was sixth-fastest behind leader Marco Bezzecchi in the first free practice in Thailand on Friday as the new season got underway.
Marquez launches his bid for a record-equalling eighth world title this weekend in Buriram after dominating the competition last season.
The Spaniard has said he is still suffering the lingering effects of a shoulder injury that forced him to miss the final four races of last season.
The Ducati rider said the injury has forced him to change his riding style until he is back to full fitness.
Marquez was 0.426 sec behind Aprilia's Bezzecchi as the action got going in dry conditions.
Bezzecchi clocked a fastest lap of 1 minute 29.346 seconds, putting him top of the timesheets, 0.110 of a second ahead of VR46's Fabio Di Giannantonio.
Aprilia's Jorge Martin, the 2024 world champion, was third ahead of Trackhouse's Ai Ogura and KTM's Pedro Acosta.
Martin, whose defence of his title last season was wrecked by injuries, crashed 10 minutes into the session.
Francesco Bagnaia, the 2022 and 2023 world champion, was seventh, one place behind his Ducati teammate Marquez.
Alex Marquez, last season's championship runner-up, was ninth.
Turkey's Toprak Razgatlioglu, a three-time Superbike world champion making his MotoGP debut, was 21st.