The 21-year-old opener, playing in his 27th one-day international, faced 131 deliveries, including seven boundaries, en route to his fifth ODI century.
He reached this milestone by taking a risky single off fast bowler Josh Hazlewood, which turned into two runs due to an errant throw at the stumps.
At the time of his century, Afghanistan had reached 216-4 after 44 overs, having won the toss against Australia, who are five-time World Cup champions.
A victory in this match would secure Australia a spot in the semi-finals.
Despite being a surprise package in the tournament, Afghanistan remain in contention for a place in the last four with four wins in seven matches, including victories over reigning champions England, 1992 title-winners Pakistan, and 1996 champions Sri Lanka.