Maverick Vinales ended a 25-race win drought for Yamaha with a dominant victory in a chaotic MotoGP Australian Grand Prix, while World Champion Marc Marquez retired following a scary collision with Johann Zarco.
Vinales recovered from a sluggish start to take the lead early on to ease to Yamaha's first win since Assen last year, while Andrea Iannone fended off Andrea Dovizioso for second.
Danilo Petrucci made a blinding start from eighth on the grid to lead into Turn 1, but dropped to the back of the pack after running off track at the second turn, with Pramac team-mate Jack Miller picking up the mantle in front of his home crowd.
Marquez scythed past Miller at the start of the second lap, with Andrea Dovizioso following suit on his Ducati stablemate to begin the charge against the Honda man.
Pre-race favourite Andrea Iannone engaged with Dovizioso on lap four at the Honda hairpin, but ran wide and allowed Dovizioso to resume his hunt of the reigning world champion.
Dovizioso found, caught and passed Marquez on the next tour, while the Honda rider's race came to a scary early end when Zarco collided with him on the run into Doohan corner.
Zarco escaped uninjured despite a fast slide through the run-off at Turn 1, while the damage to Marquez's RC213V forced him to retire for the first time this season.
After making a poor start from second, Vinales carved his way through the pack and passed Dovizioso for the lead on lap eight, with team-mate Valentino Rossi following suit two tours later.
Vinales was able to build up a gap of a second almost immediately, which only continued to open up as the battle for second raged between Rossi, Dovizioso, Iannone and works Ducati stand-in Alvaro Bautista.
With three laps remaining, Iannone found his way into second after a daring move on Dovizioso at the Hayshed and began to bite into Vinales' lead, cutting it from close to four seconds to two by the start of the penultimate tour.
Vinales' responded to Iannone's late charge, and maintained his two-second advantage to claim his first victory since the 2017 French Grand Prix.
Dovizioso put late pressure on Iannone for second, but was just held at bay, while Bautista finished a fine fourth on his factory Ducati debut ahead of the second Suzuki of Alex Rins.
Rossi faded to sixth late on ahead of home hero Miller, while Franco Morbidelli ended the race as top Honda runner on his year-old Marc VDS RC213V in eighth.
Aleix Espargaro guided his developmental RS-GP to ninth ahead of KTM's Bradley Smith, with Karel Abraham 11th on his first outing on the Nieto GP17 ahead of a recovering Petrucci, Scott Redding [Aprilia], Takaaki Nakagami [LCR] and Xavier Simeon [Avintia]
Dani Pedrosa compounded a tough day for the factory Honda team after crashing out at Turn 4, while Hafizh Syahrin dropped out of the top 10 after dropping his Tech3 M1 at the same place. Pol Espargaro pulled out with a technical issue on his KTM with four laps to go.
