Marco Bezzecchi's domination of the Mandalika timesheets, stretching from Friday afternoon until victory in the Sprint, ended in morning warm-up for the Indonesian MotoGP.
Yamaha's Fabio Quartararo officially finished the session on top with a 1m 30.345s, but newly crowned world champion Marc Marquez fired a warning by setting a slightly quicker 1m 30.239s - cancelled due to track limits.
While Quartararo stuck with the soft rear from the Sprint, Marquez joined most of the field in moving up to the medium rear ahead of the 27-lap grand prix and enjoyed his best session of the weekend.
"Today, it was quite windy here in turn 7-8," Marquez said after warm-up. "But the track is every day a bit better and better. But let's see. It will not be an easy day for us."
The Ducati Lenovo rider had to serve a long lap penalty on his way to seventh place, sixth after a penalty for Luca Marini, for contact with Alex Rins on the opening lap.
"Here, as soon you try to overtake somebody, you go on the dirty part and it's impossible to stop the bike. But of course, we will try to be a bit more careful in Turn 10, sorry for Alex yesterday!"
Quartararo, Fabio di Giannantonio, Franco Morbidelli and Miguel Oliveira kept the soft rear tyre for warm-up, indicating they are seriously considering a gamble this afternoon.
The Yamaha riders, especially, have struggled to generate heat in the medium rear.
Pramac's Jack Miller set a competitive time, just 0.299s behind Quartararo (for eighth) on a new medium tyre this morning, suggesting the M1 can make it work.
However, team-mate Miguel Oliveira was only slightly slower than Miller on a soft rear that had done 16 laps, underlining the tricky choice to be made.
Bezzecchi was one place ahead of the Australian, on a new medium rear tyre and an old soft front. "Today is super-hot, more than the past days, but I felt good," he said after warm-up.
Between Marc and Bezzecchi - and all on soft front, medium rear tyres - were Alex Marquez, Gresini team-mate and Sprint runner-up Fermin Aldeguer, Saturday's podium finisher Raul Fernandez and Honda's Luca Marini, demoted from sixth by a tyre pressure penalty in the Sprint.
Franco Morbidelli and KTM's Pedro Acosta completed the top ten, but Francesco Bagnaia's Mandalika woes continued with just 17th place on the same soft-medium tyre combination as team-mate Marc Marquez.
Directly behind was fellow GP25 rider Fabio di Giannantonio, albeit on a very old 21-lap soft rear tyre, with LCR rookie Somkiat Chantra completing the field.