The Styrian Grand Prix was halted after two laps following a spectacular crash involving Spaniard Dani Pedrosa and Italian Lorenzo Savadori on Sunday.
Television footage showed Pedrosa crashing first and then Savadori riding his Aprilia into the downed KTM.
The bikes came to rest in the middle of the track and caught fire.
Pedrosa, returning to MotoGP after two years as a test rider, walked away but Savadori was evacuated on a stretcher although clearly conscious.
Burning fuel spread across the track before marshalls put out the blaze. They then had to scrub away the debris and extinguisher fluid and blow-dry the track.
Because the crash occurred in the first three laps, the race was due to restart from the grid with riders in their original positions. The race was reduced to 27 laps.
The delayed start increased the chances of a thunderstorm hitting before the end of the race.