Marc Marquez re-established his command of MotoGP by defeating Jorge Lorenzo in the Aragon Grand Prix, as Dani Pedrosa crashed out.
Pedrosa's lap-six incident looks set to end his 2013 championship hopes, and came amid a battle with Honda team-mate Marquez.
Lorenzo's Yamaha had again burst into the lead at the start, but this time the Hondas soon reeled him back in.
As they did so, Pedrosa overtook Marquez. Unique among the top three in running a harder front tyre, Pedrosa looked like he might have a race pace advantage.
A few laps later, Marquez surged back down the outside of Pedrosa to try to reclaim second, but ran wide over the run-off area.
At the same moment, Pedrosa launched into a violent high-side on the exit of the corner and crashed into retirement.
He was checked in the medical centre for a potential left knee injury but escaped without serious damage.
Marquez was now two seconds behind Lorenzo, a gap he chipped away at until slipping into the lead with six laps remaining.
Lorenzo tried to fight back and closed in again, only for a final spurt from Marquez to give him victory by 1.3 seconds.
Valentino Rossi returned to the podium in third on the second Yamaha.
He had to fight hard to get there, only claiming the place after a huge, race-long dice that also involved Alvaro Bautista, Stefan Bradl and Cal Crutchlow.
Bradley Smith, Ducati pair Andrea Dovizioso and Nicky Hayden, and Andrea Iannone completed the top 10, with Aleix Espargaro a class apart in CRT again in 11th.
Results - 23 laps: Pos Rider Team/Bike Time/Gap 1. Marc Marquez Honda 42m03.459s 2. Jorge Lorenzo Yamaha +1.356s 3. Valentino Rossi Yamaha +12.927s 4. Alvaro Bautista Gresini Honda +13.787s 5. Stefan Bradl LCR Honda +13.973s 6. Cal Crutchlow Tech 3 Yamaha +14.662s 7. Bradley Smith Tech 3 Yamaha +31.220s 8. Andrea Dovizioso Ducati +40.671s 9. Nicky Hayden Ducati +53.413s 10. Andrea Iannone Pramac Ducati +55.067s 11. Aleix Espargaro Aspar Aprilia +58.001s 12. Yonny Hernandez Pramac Ducati +1m05.513s 13. Randy de Puniet Aspar Aprilia +1m06.589s 14. Hiroshi Aoyama Avintia FTR-Kawasaki +1m08.674s 15. Claudio Corti Forward FTR-Kawasaki +1m09.130s 16. Colin Edwards Forward FTR-Kawasaki +1m12.041s 17. Luca Scassa Cardion Aprilia +1m45.152s 18. Bryan Staring Gresini FTR-Honda +1m45.228s 19. Lukas Pesek Ioda-Suter-BMW +1m45.583s Retirements: Hector Barbera Avintia FTR-Kawasaki 8 laps Dani Pedrosa Honda 5 laps Damian Cudlin PBM-Aprilia 3 laps Danilo Petrucci Ioda-Suter-BMW 0 laps Michael Laverty PBM Aprilia 0 laps