Spain's Alex Rins stormed to a pulsating win at the Australian MotoGP on Sunday with world championship leader Fabio Quartararo crashing out to put a huge dent in his title hopes.The Suzuki rider started 10th on the grid and finished 0.186 seconds ahead of Spanish great Marc Marquez with Francesco Bagnaia coming third to move top of the championship standings.Ducati's Bagnaia started the race just two points behind reigning world champion Quartararo in the title fight and now heads to the penultimate grand prix of the season in Malaysia with a 14-point advantage.It could have been more, with the Italian leading into the final lap at the waterfront Phillip Island circuit before an audacious Rins and then Marquez passed him."It's so amazing to get this victory," said an ecstatic Rins after his fourth career MotoGP win.Quartararo on a Yamaha started fifth but made a massive mistake under braking at turn five on lap four and dropped to 22nd.He started setting fastest laps in a desperate bid to get back in the points, but overdid it on lap 10 of the 27-lap race, losing control on a corner and sliding out.The Frenchman has now failed to score in the last three Grands Prix in a horror run that has seen his title hopes fade.Australian Ducati rider Jack Miller started 40 points behind Quartararo, still with slender title hopes, and had moved up to fourth when his race also ended prematurely.Alex Marquez was at fault, smashing into him at turn four in an error that ended both of their races.Among the other title contenders, Spain's Aleix Espargaro came ninth to leave him 27 points adrift while Enea Bastianini was fifth to be 42 points behind.Jorge Martin started on pole and led for much of the early stages ahead of Marquez before