Danny Webb took his and Mahindra's first ever 125cc pole position in the series' last ever qualifying session at a damp Valencia.
Drying conditions prompted a spectacular pole battle, with Webb, Louis Rossi and Alexis Masbou choosing to go for slick tyres in the closing moments and reaping the benefits.
Championship leader Nico Terol will start only ninth, six places behind title rival Johann Zarco - although Terol needs just an 11th position to seal the crown, regardless of what Zarco does.
Webb made by far the best use of the slicks to set a string of searing provisional pole times, eventually ending on a 1m45.988s - nearly two seconds clear of the field for a while, although second-placed Rossi's Matteoni Aprilia was within half a second in the end.
Fellow slick runner Masbou was fifth on the Caretta KTM, with Zarco (Ajo Derbi) the quickest wet tyre user in third, ahead of Luis Salom's RW Aprilia.
Terol could only manage ninth for Aspar - although the eventual result was far better for the Spaniard than it had looked at one stage during the ever-changing session, when Zarco held provisional pole and Terol was only 22nd.
Hector Faubel (Aspar Aprilia), Sandro Cortese (Team Germany Aprilia) and Maverick Vinales (Blusens Aprilia) will start just ahead of Terol in sixth to eighth places, with Ajo's Jonas Folger completing the top 10.
Masbou's team-mate Jack Miller was spectacularly quick in the wet and held provisional pole for a while, before slipping to 12th as conditions improved.
Pos Rider Team/Bike Time Gap 1. Danny Webb Mahindra 1m45.898s 2. Louis Rossi Matteoni Aprilia 1m46.325s + 0.427s 3. Johann Zarco Ajo Derbi 1m48.028s + 2.130s 4. Luis Salom RW Aprilia 1m48.264s + 2.366s 5. Alexis Masbou Caretta KTM 1m48.283s + 2.385s 6. Hector Faubel Aspar Aprilia 1m48.288s + 2.390s 7. Sandro Cortese Germany Aprilia 1m48.731s + 2.833s 8. Maverick Vinales Blusens Aprilia 1m48.756s + 2.858s 9. Nicolas Terol Aspar Aprilia 1m48.920s + 3.022s 10. Jonas Folger Ajo Aprilia 1m49.438s + 3.540s 11. Adrian Martin Aspar Aprilia 1m49.456s + 3.558s 12. Jack Miller Caretta KTM 1m49.721s + 3.823s 13. Efren Vazquez Ajo Derbi 1m49.726s + 3.828s 14. Alberto Moncayo Andalucia Aprilia 1m49.779s + 3.881s 15. Zulfahmi Khairuddin Ajo Derbi 1m49.794s + 3.896s 16. Josep Rodriguez Blusens Aprilia 1m50.178s + 4.280s 17. Alessandro Tonucci Italia FMI Aprilia 1m50.345s + 4.447s 18. Danny Kent Ajo Aprilia 1m50.382s + 4.484s 19. Niklas Ajo TT Motion Aprilia 1m50.583s + 4.685s 20. Manuel Tatasciore Phonica Aprilia 1m51.023s + 5.125s 21. Sturla Fagerhaug WTR-Ten10 Aprilia 1m51.088s + 5.190s 22. Luigi Morciano Italia FMI Aprilia 1m51.162s + 5.264s 23. Marcel Schrotter Mahindra 1m51.667s + 5.769s 24. Jakub Kornfeil Ongetta Aprilia 1m51.953s + 6.055s 25. John McPhee KRP Aprilia 1m52.005s + 6.107s 26. Taylor Mackenzie Phonica Aprilia 1m52.699s + 6.801s 27. Jasper Iwema Ongetta Aprilia 1m53.063s + 7.165s 28. Peter Sebestyen Matteoni Aprilia 1m53.313s + 7.415s 29. Harry Stafford Ongetta Aprilia 1m53.370s + 7.472s 30. Giulian Pedone Phonica Aprilia 1m53.556s + 7.658s 31. Daniel Ruiz Larresport Honda 1m54.437s + 8.539s 32. Juan Francisco Guevar Pramac Aprilia 1m54.767s + 8.869s 33. Kevin Hanus Hanusch Honda 1m55.262s + 9.364s 34. Emil Petersen Nordgren Honda 1m55.406s + 9.508s 35. Marco Colandrea WTR-Ten10 Aprilia 1m56.230s + 10.332s 36. Brad Binder Andalucia Aprilia 1m56.887s + 10.989s