Australian Jack Miller has surged through the field to win the Australian Moto3 Grand Prix at Phillip Island.

Spending most of the race duelling for top position with title rival Alex Marquez, Miller made a decisive move on Doohan corner of the final lap of the race to win his home race.

The victory keeps alive his hopes of claiming a Moto3 crown, though Marquez’s second place position means the advantage gained is slight.

Miller cut Marquez’s lead in the Moto3 championship to 20 points with the win, with Alex Rins third in the blanket finish.

Starting from eighth, Miller’s task was a huge one but he quickly made a mockery of his grid position.

Miller improved his grid position to be seventh by the first bend, sixth by the end of the first lap and a key player of the leading pack.

The 19-year-old crowd favourite had the quickest lap of the race in lap three, including a sharp passing move on Danny Kent as he continued to move forward.

He announced himself as a serious challenger by taking the lead on the fourth lap.

The leading pack proceeded to play a game of cat and mouse through the race, sharing the lead through more than half a dozen riders.

But the game got serious with a few laps remaining.

A key moment came with four laps to go as Marquez misjudged a bend to slip to ninth and the back of the lead pack – with Miller at the front.

But Marquez surged again to re-take the lead within two laps.

Miller was not to be denied, overtaking both Marquez and Rins on the final lap to steal victory.

Remy Gardner, given a wildcard to race on the straight named after his world champion father Wayne, saw his hopes of impressing hit by a problem in the warm-up lap.

Starting from the pit lane, his race became about catching the field rather than racing in it.

By lap 10, he was able to compete and finished 26th after duelling with front-rower Juanfran Guevara.

Fellow wildcard rider Olly Simpson enjoyed his debut grand prix ride but failed to make an impact, finishing last.

A field of 28 finished the race, with five forced to withdraw.

While the Australian winner celebrated strongly in front of his home crowd, championship leader Marquez showed his delight with the result after the race, knowing a 20-point lead with two races remaining is potentially a title-winning one.