Alex Debon claimed the last ever 250GP pole position during qualifying at Valencia on Saturday, then crashed heavily just seconds after setting his best lap time.
The Aeropuerto-Castello-Blusens rider improved on his pole time with one minute to go, but got into a tank-slapper at turn one - forcing him to spear straight on into the gravel, before being harshly dumped from his Aprilia.
Instead of celebrating his second pole of the year, the Spaniard was taken to the medical centre on a stretcher.
Hiroshi Aoyama - who will start Sunday's race with a 21 point advantage over reigning champion Marco Simoncelli and therefore just needs to finish in the top eleven to claim the final 250cc crown - qualified in fifth position for Scot Honda, with Simoncelli second for Metis Gilera.
Starting between Simoncelli and Aoyama will be Hector Barbera (Pepe World Aprilia) and Ratthapark Wilairot, who claimed his first front row start with fourth for the Thai Honda PTT team.
Former title contender Alvaro Bautista will line-up just ninth for his final race with Aspar Aprilia before joining Aoyama, Simoncelli and Barbera in moving to MotoGP in 2010.
The new Moto2 class will replace 250GP from 2010. The first 250cc World Championship was held during the inaugural year of motorcycle grand prix racing, in 1949.
Qualifying - Valencia:
1. Debon (Aprilia) 1min 36.116sec
2. Simoncelli (Gilera) +0.334sec
3. Barbera (Aprilia) +0.354sec
4. Wilairot (Honda) +0.447sec
5. H. Aoyama (Honda) +0.540sec
6. Luthi (Aprilia) +0.869sec
7. Abraham (Aprilia) +1.155sec
8. Pasini (Aprilia) +1.162sec
9. Bautista (Aprilia) +1.187sec
10. Faubel (Honda) +1.202sec
25. Dunlop (Honda) +6.790sec