But not for long! Luca Marini, also on the revised medium front, and a medium rear, is fastest.
Acosta almost clips the back of Bagnaia.
FP1 at the Indonesian MotoGP ends with Luca Marini fastest from Pedro Acosta. Both put a new medium front tyre on at the end. The Italian also put a new medium rear while Acosta kept an old medium rear.
But not for long! Luca Marini, also on the revised medium front, and a medium rear, is fastest.
Acosta almost clips the back of Bagnaia.
Acosta keeps his RC16 under control and goes fastest, by 0.290s. 1min to go.
Lots of red sectors flashing up on the screens for the final minutes.
Alex Rins is into 3rd place, then goes fastest! Surprisingly, the tyre data says he's on old rubber.
Pedro Acosta is the latest rider to save a big moment. Acosta is 8th fastest with 3mins to go.
Gigi Dall’Igna and Uccio Salucci appear surprised when Uccio's quote about Morbidelli's bike being given to Bagnaia at the Misano test is flashed up on the TV screen!
Marc Marquez runs off track and across the gravel as he rejoins the track from pit lane. Continues without issue. He's still 0.067s ahead of Bezzecchi.
There we go.... VR46's Alessio Salucci confirms to Dorna's Jack Appleyard that Francesco Bagnaia had Franco Morbidelli's GP24 at the Misano MotoGP test.
Francesco Bagnaia has slipped back to 16th place, +1.2s, using the same hard and soft tyre selection as Marc Marquez.
Marquez meanwhile, runs off at Turn 1 after a moment on corner entry.
Replays show Maverick Vinales make a big leg-off save after losing the front of his KTM at high speed. Vinales is still recovering from his Sachsenring shoulder injury.
Marco Bezzecchi might still be sore from Motegi but he's enjoying a story start, closing to within 0.067s of Marc Marquez.
Pedro Acosta climbs to third for KTM, +0.297s.
A promising start for Honda, with all 4 riders still in the top ten.
Halfway through FP1 and it's still Marc Marquez from Johann Zarco and Jack Miller.
For reference, last year's Sprint saw most riders race with the hard front and soft rear tyres, then fit the medium rear for the grand prix.
15mins gone:
It's worth repeating that FP1 usually sees riders fitting tyres they don't expect to need for qualifying or the races; there's no point using up the 'best' tyre compounds on a dirty track.
A change at the top as Marc Marquez goes fastest, by 0.259s, on his 8th lap. Like Bezzecchi, he's using the hard front and medium rear tyres.
It's now an Aprilia one-two with Trackhouse rider Raul Fernandez putting the special Gulf livery into second behind Bezzecchi. Johann Zarco 3rd, Fabio Quartararo 4th, Alex Rins 5th.
Francesco Bagnaia is only 18th after 5 laps.
So far, it's Marco Bezzecchi fastest for Aprilia, ahead of Yamaha's Fabio Quartararo and Honda rookie Somkiat Chantra, now confirmed as moving to WorldSBK next season.
On track and Gresini's Fermin Aldeguer becomes the first faller of the weekend. A front-end accident at Turn 8. Rider OK.
Gigi Dall’Igna's cuts and scrapes are explained by Dorna's pit lane reporter Jack Appleyard, who says that Dall’Igna dived into the shallow end of a swimming pool earlier this week.