The Ducati rider received medical treatment and was conscious after the horrifying accident.
The Ducati rider set off from pole, avoiding a multi-bike pile up at turn one.
Then at the next corner Bagnaia lost control, the Italian thrown violently into the air in front of the chasing pack. Brad Binder’s KTM then ran over Bagnaia’s leg.
The runaway series leader was conscious, and taken away to the track’s medical centre in an ambulance, with the crowd clapping him.
Bagnaia leads the championship by 66 points form Jorge Martin up to his crash.
The race was red-flagged immediately as officials got to work to clear the track of debris and oil.
The race restarted for 23 of the 24 laps.
Also missing was Enea Bastianini, one of the fallen riders also taken to the medical centre for a check-up.
(With inputs from AFP)