Australia's cricketers won the game but lost control of their T20 World Cup fate.
Australia pipped Afghanistan by just four runs in Adelaide on Friday night, making 8-168 and holding the visitors to 7-164.
But the narrow margin was not enough for Australia to overtake England's net run rate.
If England beat Sri Lanka on Saturday night, they will join New Zealand as their group's semi-finalists and Australia's title defence will be over - and captain Aaron Finch's international career will likely come to an end too.
Australia refused to gamble on the fitness of Finch and middle-order blaster Tim David for the Afghanistan clash, both ruled out with hamstring injuries.
But selectors took a massive punt by axing Australia's highest T20 wicket-taker Mitchell Starc in favour of Kane Richardson.
Richardson, who pre-match had a better career strike-rate and average than Starc, returned figures of 1-48 from four overs.
Australia's batting replacements Cameron Green and Steve Smith failed to fire, making three and four respectively and facing just six balls between them.
Green and Smith fell cheaply in an Australian innings highlighted by Glenn Maxwell (54no from 32 balls) and Mitchell Marsh (45 from 30).
Opener David Warner (25 from 18) revved early but was dismissed in reverse: he moved to switch-hit but, shaped as a right-hander, was clean bowled.
Marcus Stoinis (25 from 21) failed to hit top gear and stand-in skipper Matthew Wade made six as Australia lost their last four wickets in a 20-run span.
The Australians needed to bowl the Afghans out for 106 or less to overtake England on net run rate.
That goal disappeared in the 16th over, leaving Australia's semi-final hopes hanging on an upset Sri Lankan victory over England.
New Zealand (seven points, net run rate 2.113) top the group with Australia (seven points, minus 0.173) now second.
An England triumph will also lift them to seven points but they already boast a net run rate of 0.547.
Injured skipper Finch, already retired from one-day internationals, is tipped to also call stumps on his career in the shortest format, with Australia's next T20 fixtures not until August next year in South Africa.
Finch was a nervy spectator as Afghan hero Rashid Khan threatened to end Australia's cup hopes on Friday night.
After the Afghans lost 4-3 to be 6-103 in the 15th over, Rashid cracked four sixes and three fours in smashing 48no from 23 balls.
The visitors required 21 from Stoinis' last over but Rashid fell just shy of producing a sporting miracle.
