Championship leader Julian Simon has taken pole position with his Aspar Aprilia ahead of the 125cc Indianapolis Grand Prix.
With five minutes to spare in the 40-minute session, the Spaniard shot to the top of the timesheets with a 1m49.337s lap to push Ajo Derbi's Sandro Cortese down to second.
The German, who grabbed provisional pole just a few seconds earlier, managed to further improve his lap time in the closing minutes, but in the end had to be content with being half a tenth slower than Simon.
Nicolas Terol took third spot with his Jack&Jones Aprilia, with Pol Espargaro's Derbi completing the front row after leading most of the session.
Simon's team-mate Bradley Smith looked able to fight for pole thanks to often setting the quickest time in the Brickyard's first three sectors. The Briton, however, would always lose out in the final sector, and in the end only qualified fifth.
The Aprilias of Simone Corsi (Fontana) and Sergio Gadea (Aspar) will take the sixth and seventh slots of the grid, with Derbi's Efren Vazquez rounding up the second row.
Stefan Bradl (Kiefer Aprilia), Marc Marquez (KTM) and Randy Krummenacher (Degraaf Aprilia) all suffered crashes during the session.
Pos Rider Bike Time 1. Julian Simon Aprilia 1m49.337s 2. Sandro Cortese Derbi 1m49.387s + 0.050s 3. Nicolas Terol Aprilia 1m49.537s + 0.200s 4. Pol Espargaro Derbi 1m49.577s + 0.240s 5. Bradley Smith Aprilia 1m49.585s + 0.248s 6. Simone Corsi Aprilia 1m49.628s + 0.291s 7. Sergio Gadea Aprilia 1m49.661s + 0.324s 8. Efren Vazquez Derbi 1m49.703s + 0.366s 9. Marc Marquez KTM 1m49.852s + 0.515s 10. Joan Olive Derbi 1m49.853s + 0.516s 11. Daniel Webb Aprilia 1m49.982s + 0.645s 12. Andrea Iannone Aprilia 1m50.140s + 0.803s 13. Johann Zarco Aprilia 1m50.340s + 1.003s 14. Michael Ranseder Aprilia 1m50.494s + 1.157s 15. Stefan Bradl Aprilia 1m50.530s + 1.193s 16. Tomoyoshi Koyama Loncin 1m50.547s + 1.210s 17. D.Agerter Derbi 1m50.721s + 1.384s 18. Lorenzo Savadori Aprilia 1m50.728s + 1.391s 19. Takaaki Nakagami Aprilia 1m50.916s + 1.579s 20. Luis Salom Aprilia 1m51.006s + 1.669s 21. Jonas Folger Aprilia 1m51.062s + 1.725s 22. Esteve Rabat Aprilia 1m51.470s + 2.133s 23. Cameron Beaubier KTM 1m51.527s + 2.190s 24. Lorenzo Zanetti Aprilia 1m51.539s + 2.202s 25. R.Krummenacher Aprilia 1m51.546s + 2.209s 26. Scott Redding Aprilia 1m51.569s + 2.232s 27. Luca Marconi Aprilia 1m52.334s + 2.997s 28. Lukas Sembera Aprilia 1m52.373s + 3.036s 29. Alexis Masbou Loncin 1m52.448s + 3.111s 30. Miles Thornton Aprilia 1m53.835s + 4.498s 31. Luca Vitali Aprilia 1m54.107s + 4.770s 32. Ben Young Aprilia 1m56.451s + 7.114s