Marc Marquez resumed his unstoppable form in 125cc qualifying at Indianapolis, taking his seventh pole of the season.
The championship leader and five-time race-winner put his Ajo Derbi on provisional pole by over a second with one of his first runs and looked like he would remain untouchable for the full 40 minutes.
A mighty effort by Aspar Aprilia's Nico Terol got the Spaniard in front in the closing stages - but only for a few minutes before Marquez put in a 1m48.124s lap to reclaim pole by nearly half a second. He had also been fastest in both practice sessions, despite lingering pain from a dislocated shoulder suffered at Brno a fortnight ago.
Terol's team-mate Bradley Smith took third, with Marquez's team-mate Sandro Cortese in fourth.
Title contender Pol Espargaro crashed early on, and though he instantly got back on the bike and continued with the session, he could only manage fifth - leaving him off the front row of the grid for the first time this year.
Another man to crash and rejoin was Danny Webb, who had a heavy accident on his first flying lap of the session and looked to be sidelined for the rest of qualifying at least, only to bravely resume running later and take 11th.
Pos Rider Bike Time Gap
1. Marc Marquez Derbi 1m48.124s
2. Nicolas Terol Aprilia 1m48.603s + 0.479s
3. Bradley Smith Aprilia 1m49.026s + 0.902s
4. Sandro Cortese Derbi 1m49.110s + 0.986s
5. Pol Espargaro Derbi 1m49.664s + 1.540s
6. Efren Vazquez Derbi 1m49.769s + 1.645s
7. Luis Salom Aprilia 1m49.938s + 1.814s
8. Johann Zarco Aprilia 1m50.010s + 1.886s
9. Tomoyoshi Koyama Aprilia 1m50.027s + 1.903s
10. Esteve Rabat Aprilia 1m50.078s + 1.954s
11. Danny Webb Aprilia 1m50.095s + 1.971s
12. Jonas Folger Aprilia 1m50.150s + 2.026s
13. Randy Krummenacher Aprilia 1m50.283s + 2.159s
14. Simone Grotzkyj Aprilia 1m50.384s + 2.260s
15. Alberto Moncayo Aprilia 1m50.510s + 2.386s
16. Alexis Masbou Aprilia 1m50.690s + 2.566s
17. Marcel Schrotter Honda 1m50.992s + 2.868s
18. Jakub Kornfeil Aprilia 1m51.031s + 2.907s
19. Jasper Iwema Aprilia 1m51.181s + 3.057s
20. Adrian Martin Aprilia 1m51.323s + 3.199s
21. Lorenzo Savadori Aprilia 1m51.430s + 3.306s
22. Isaac Vinales Lambretta 1m52.157s + 4.033s
23. Zulfahmi Khairuddin Aprilia 1m52.529s + 4.405s
24. Louis Rossi Aprilia 1m52.572s + 4.448s
25. Marco Ravaioli Lambretta 1m53.031s + 4.907s
26. Luca Marconi Aprilia 1m53.517s + 5.393s
27. Kristian Lee Turner Aprilia