Joan Mir wrapped up this year's Moto3 championship with two rounds to spare after taking his ninth victory of the season in a shortened Phillip Island race.
The Spaniard arrived in Australia with a 55-point advantage over nearest rival Romano Fenati, after his lead was slashed dramatically the previous weekend at Motegi following a dismal ride to 17th in the wet - his first non-score of the season.
Mir therefore needed a top-two finish in Phillip Island to guarantee himself the crown regardless of what Fenati could do, or avoid being outscored by the Italian by six points.
Starting third, Mir was in the lead group throughout the race, and was running fifth when it was red-flagged with eight laps to go due to a rain shower.
However, with the results being rolled back by a lap, it meant Mir was declared the winner, three tenths clear of Leopard Honda team-mate Livio Loi.
Polesitter Jorge Martin (Gresini Honda) was third, 0.008s behind Loi, while Fenati (Snipers Honda) - who dominated at Motegi to keep his faint title hopes alive - was only sixth.
Mir will graduate to Moto2 next season with the Marc VDS squad, which currently leads the intermediate class with Franco Morbidelli.
The Italian rider extended his points lead over his 2018 MotoGP team-mate Thomas Luthi to 29 points by finishing third behind KTM pair Miguel Oliveira and Brad Binder in Australia.