A late dash from Fabio Quartararo saw the new Leopard KTM rider shift to the top of the timesheets as practice for Moto3 drew to a close under the Qatar floodlights in Losail.
The Frenchman looked to have seamlessly managed the change from Honda to KTM machinery as he rocketed to first place on the day, but his best time of 2m 05.859s was just short of Livio Loi's record best from Thursday's second session.
Solid lapping saw Brad Binder take second on the Red Bull KTM Ajo, with Loi third for RW Racing to cement his excellent day one run.
The Spanish Moto3 Champion Nicolo Bulega was again the top rookie in fourth on Friday as the teenager continues to impress in his first Grand Prix weekend.
Just behind the Italian his countryman and senior team-mate at Sky Racing VR46 Romano Fenati posted the fifth best time of the day.
Enea Bastianini (Gresini) made massive improvements for sixth, as did Andrea Migno on the third Sky entry in seventh.
Red Bull rookie champion Bo Bendsneyder slotted into eighth for the Red Bull team with Jorge Martin the top Mahindra in ninth for the Aspar team.
Niccolo Antonelli had already set his a time good enough for tenth before his bike shook and snaked away from him at turn seven. His Honda smacked into him before it parked in the middle of the track. The Ongetta-Rivacold rider looked troubled by a pain in his collarbone as he left the track.
When time times are combined for an overall view of practice for the class, Loi holds first, with Quartararo and Binder among the few to improve moving into second and third respectively.
Mir holds fourth, Bulega fifth, Fenati sixth and Bagnaia seventh – his time from yesterday coming under scrutiny with rumours of 2015 parts being used as he finished 28th in FP3.
Locatelli, Kornfeil and Antonelli complete the combined top ten.
Estrellas Galicia's Jorge Navarro also crashed out while searching the limits of his bike, after a great save from touching the astroturf - a mix of dirty tyre and folding front saw him finally succumb to a fall.
An early crash at turn ten involving Darryn Binder and John McPhee stalled their progress ahead of Saturday's qualifying, with the Briton already struggling to improve his chassis worries with the Peugeot MC Saxoprint.
The man from Oban finished the day 26th leaving him 27th overall, his team-mate Alexis Masbou, victor at Qatar last year was 29th in today's session.
Adam Norrodin also crashed during the final practice session.