Steve Smith was unbeaten on 19 after Matthew Short was dismissed for 20. Heavy rain stopped play and as water pooled in the stadium the umpires ended the match.
Afghanistan had scored 273 all out in 50 overs after they won the toss and chose to bat. Sediqullah Atal hit 85 and all-rounder Azmatullah Omarzai 67 as they sought a win to seal a semifinal berth.
In overcast conditions, Afghanistan lost opener Rahmanullah Gurbaz for a duck in the first over to Spencer Johnson.
Ibrahim Zadran, hero of Afghanistan’s win over England with the highest-ever Champions Trophy score of 177, added 67 for the second wicket with Atal before he fell for 22 to spinner Adam Zampa.
Atal and skipper Hashmatullah Shahidi (20) put on 68 for the fourth wicket before Australia fought back with four wickets for 40 runs. Atal’s 95-ball innings included six fours and three sixes.
At 199-7 Afghanistan were in danger of being dismissed for a below-par total, but Omarzai held the innings together, smashing five sixes in a 63-ball knock and adding an invaluable 74 runs with the last three wickets. Rashid Khan chipped in with a 17-ball 19 with two boundaries.
Ben Dwarshuis was the best Australian bowler with 3-47. Zampa took 2-48 and Johnson finished with 2-49.