With each side taking a point from the rained-off tie Australia, on two points, can no longer catch Zimbabwe, on five, even if they win their final match against Oman on Friday (Saturday 0030 AEDT).
Heavy rain in Kandy meant the covers were on the Pallekele International Stadium for much for day before the match was finally called off three hours after the scheduled toss.
Zimbabwe thus go through to the Super Eight stage alongside Sri Lanka, with Thursday's match between the teams deciding who tops group B.
It is the first time Australia have been knocked out of a World Cup at the group stage, in either the T20 or ODI formats, since 2009. Their only victory was over Ireland, who were also eliminated by the washout.
It was defeat by Sri Lanka that KO'd Australia in both cases, in Nottingham in 2009 and Kandy on Monday, but the real damage this time was done by the loss to Zimbabwe.
The African side did not qualify for the last World Cup, in 2024, and had to start their journey to this event in October that year, in the sub-regional Africa B tournament. They won ten successive qualifiers to get to the World Cup, and two more in Sri Lanka prior to this match.
Exiting due to a washout summed up Australia's benighted campaign. They came into the event ranked third in the world but never looked like justifying that billing.
Injuries have played a part, notably to powerplay specialist Josh Hazlewood, but also to Pat Cummins. Without them Australia's attack has struggled taking 4-353 in 38 overs against Zimbabwe and Sri Lanka, with three of those wickets going to Marcus Stoinis.
The batting too, has been short of form and coherence.
Captain Mitch Marsh missed the opening two matches after suffering a painful testicular injury in training while a hamstring injury incurred in December meant Tim David did not come back into the side until the Zimbabwe game, and looked undercooked.
Most of the other batters have struggled for runs for some time, making the decision to drop Matt Renshaw, who made 65 against Zimbabwe, nor play the in-form Steve Smith having called him up, a curious one.
The pre-tournament tour of Pakistan ended in defeats by 22, 90 and 111 runs, with only Green (twice) and Xavier Bartlett reaching 30 in the three innings. Australia did field a weakened team, with some players late to arrive due to BBL commitments and others omitted or rested due to injury, but that only underscored the inadequate preparation.
Australia will co-host the next tournament in October 2028 with New Zealand. T20 is likely to rise in priority as that nears, not least with cricket making an Olympic return, in that format, at Los Angeles 2028.
A rebuild seems inevitable. Only three players in the current squad, Green, Bartlett and Connolly Cooper, will be under the age of 30 come the next T20 World Cup while Marsh, Hazlewood, Stoinis, Smith, Glenn Maxwell, Adam Zampa, Sean Abbott and Ben Dwarhuis will be past their 36th birthdays with Cummins (35), Head, David and Nathan Ellis (all 34) not far behind.
Meanwhile, as Australia kick their heels waiting for their remaining game, the tournament goes on with Pakistan set to take the final Super Eights place if they beat Namibia on Wednesday.
SUPER EIGHTS
GROUP A: India, West Indies, South Africa, Zimbabwe.
GROUP B: Sri Lanka, England, New Zealand, Pakistan or USA.
