Marc Marquez slashed Stefan Bradl's championship lead from 43 points to 28 by taking a battling victory at the Moto2 Indianapolis Grand Prix.
The 18-year-old Spaniard failed to make the most of his pole position and ran third during the early stages behind Bradley Smith - who jumped into the lead at the first corner - and Simone Corsi.
But steadily he picked off the pair, slipstreaming past Smith's Tech 3 along the start/finish straight on the second lap and then spending only six more tours behind Corsi's Ioda FTR before repeating the move.
After that the Catalunya Suter rider was able to pull away and went on to take his fifth win of the year - and his fourth in the last five races - by 1.889s.
Behind him the order never stopped changing with the battle for second initially being disputed by Corsi, Smith, Andrea Iannone's Speed Master Suter, Esteve Rabat's Blusens FTR and Scott Redding's Marc VDS Suter.
With Corsi steadily falling back, Iannone looked the most likely threat to Marquez, but the Italian slid wide at Turn 1 on lap 14 and slipped back to fourth spot behind Rabat and Pol Espargaro, who had closed in on the podium battle at one third distance.
Moto2 rookie Espargaro - who lay only 23rd in the championship coming into the race - took just a few more laps to stick his Speed Up FTR inside Rabat to grab second and went on to claim his maiden podium finish in the class.
Rabat remained on his tail to the finish and took his own best finish in the category. Smith and Redding were next up, the pair closing in on the rostrum battle by the finish.
Bradl, who had started way down in 22nd after a problematic time in practice and qualifying, produced the ride of the race on his Kiefer Kalex. The German lay only 20th at the end of the first lap, but preserved his tyres early in the race and was able to pounce later on as others ran into trouble with them.
The championship leader passed Dominique Aegerter to move into the top 10 at half-distance and continued his rise by passing Ioda team-mates Corsi and Mattia Pasini, Julian Simon's Aspar Suter and then Iannone to make it up to sixth by the flag.
Pasini finished eighth ahead of Redding's team-mate Mika Kallio and the Pons Kalex of Espargaro's older brother Aleix, while Iannone fell back to 11th.
Corsi was among the worst affected by tyre troubles, the Italian almost crashing twice in a lap after losing the lead to Marquez. He slipped back to 14th by the finish, three places ahead of Thomas Luthi - another man who ended the first lap inside the top five.
Pos Rider Team/Bike Resultt/Gap 1. Marc Marquez Catalunya Suter 45m50.601s 2. Pol Espargaro Speed Up FTR + 1.889s 3. Esteve Rabat Blusens FTR + 2.310s 4. Bradley Smith Tech 3 + 3.389s 5. Scott Redding Marc VDS Suter + 5.674s 6. Stefan Bradl Kiefer Kalex + 9.134s 7. Julian Simon Aspar Suter + 9.347s 8. Mattia Pasini Ioda FTR + 15.010s 9. Mika Kallio Marc VDS Suter + 15.031s 10. Aleix Espargaro Pons Kalex + 15.339s 11. Andrea Iannone Speed Master Suter + 17.447s 12. Dominique Aegerter Technomag-CIP Suter + 21.727s 13. Xavier Simeon Tech 3 + 24.279s 14. Simone Corsi Ioda FTR + 25.714s 15. Alex de Angelis JIR Motobi + 26.894s 16. Jules Cluzel Forward Suter + 27.375s 17. Thomas Luthi Interwetten Suter + 27.546s 18. Jordi Torres Aspar Suter + 27.764s 19. Ricard Cardus QMMF Moriwaki + 27.946s 20. Michele Pirro Gresini Moriwaki + 29.362s 21. Randy Krummenacher Kiefer Kalex + 31.701s 22. Claudio Corti Italtrans Suter + 32.030s 23. Raffaele de Rosa Forward Suter + 32.100s 24. Max Neukirchner MZ + 35.387s 25. Yuki Takahashi Gresini Moriwaki + 37.801s 26. Anthony West MZ + 42.146s 27. Mike di Meglio Tech 3 + 53.491s 28. Martin Cardenas Blusens FTR + 58.947s 29. JD Beach Castello FTR + 1m04.334s 30. Valentin Debise Speed Up FTR + 1m12.230s 31. Jake Gagne GP Tech FTR + 1m12.503s 32. Robertino Pietri Italtrans Suter + 1m15.177s 33. Santiago Hernandez SAG FTR + 1m15.899s 34. Alex Baldolini Pons Kalex + 1m37.102s 35. Mashel Al Naimi QMMF Moriwaki + 1 lap Retirements Ratthapak Wilairot SAG FTR 21 laps Carmelo Morales La Torre Moriwaki 15 laps Kenny Noyes Avintia FTR 7 laps