Reigning World Champion Marc Marquez put in a clinical performance at MotoGP's Spanish Grand Prix to take the title lead, as his primary rivals came to blows in a dramatic incident.
Marquez started from fifth at Jerez but worked his way through to the lead, with his win effectively sealed when Jorge Lorenzo, Andrea Dovizioso and Dani Pedrosa collided at the hairpin.
Marquez quickly overhauled polesitter Cal Crutchlow and front-row starter Johann Zarco, before dispatching Repsol Honda team-mate Pedrosa, and shadowed leader Lorenzo.
Lorenzo had shot off the line and into the lead, using Soft tyres, where he remained for several laps, until Marquez eventually made a clean move into the final corner.
Marquez opened a small gap up front and survived a scare when he lost the rear of his RC213V on gravel left by Tom Luthi at Turn 11, though he saved the moment and continued atop the pack.
As Marquez edged clear, Lorenzo began to hold up Ducati team-mate Dovizioso, who had recovered from a subdued first lap, with the pair almost clashing at the final corner.
Dovizioso regrouped and had another attempt into the hairpin, but both riders drifted slightly wide, allowing fourth-placed Pedrosa to attempt a cutback on the inside line.
Pedrosa and Lorenzo made contact as they exited the turn, sending Pedrosa into a horrible high-side, while Lorenzo's bike was pushed into the path of Dovizioso, and the Ducati pair also came crashing to the ground.
The trio were able to walk away from the incident, and the pursuing riders fortunately avoided Pedrosa's stricken bike, which had come to a halt in the middle of the track; stewards investigated the clash, but deemed no further action necessary.
Their clash left Marquez with a substantial lead and he duly reeled off the remaining laps, waving to the crowd through the final sector, to secure back-to-back MotoGP wins, and his first at Jerez since 2014.
Zarco was promoted to a lonely second position, having been on course for fifth, while a scrap for sixth position suddenly became the fight for third.
Suzuki's Andrea Iannone held the spot for much of the race though was demoted by Pramac's Danilo Petrucci – only to re-take the position a few laps later, in the process claiming successive podium finishes for Suzuki.
Petrucci was fourth, while Valentino Rossi salvaged fifth position on a lacklustre weekend for the factory Yamaha squad, fending off the advances of Jack Miller.
Maverick Vinales dropped to as low as 12th but ultimately came home in seventh, ahead of Alvaro Bautista and lead rookie Franco Morbidelli.
KTM wildcard rider Mika Kallio won the battle between the Austrian manufacturer's three representatives, ahead of Pol Espargaro, while Bradley Smith slipped behind Takaaki Nakagami late on.
Tito Rabat and Scott Redding rounded out the points scorers in a race of high attrition.
Along with the aforementioned trio, and Luthi, erstwhile polesitter Crutchlow slid out of fourth spot at Turn 1, while Alex Rins crashed in the final sector, throwing away fifth.
Karel Abraham was another crasher, while Aprilia's Aleix Espargaro pulled to the side of the circuit early on amid a suspected technical failure.