Australia have suffered a shock 21-run loss to Afghanistan that throws their semi-final hopes into jeopardy at the Twenty20 World Cup.
Mitch Marsh's side were left to rue dropping five catches in the field on Sunday (AEST) and then falling to 3-32 in the powerplay on a tough St Vincent wicket.
Chasing 149, Australia were all out for 127 with four balls remaining in the last over.
The loss means the Aussies may rely on net run-rate to make the tournament's final four even if they are able to beat India in their last Super Eight game on Tuesday (AEST).
"We were outplayed tonight," Marsh said.
After Australia won the toss, Pat Cummins (3-28) put the breaks on Afghanistan (6-148) with his second hat-trick in as many games before Glenn Maxwell was the other key contributor in the fight to avoid an upset.
Maxwell (59 off 41 balls) batted himself back into form and threatened to reprise his role as Afghanistan's bogeyman following a double-century at the 2023 ODI World Cup.
But this time, Afghan openers Rahmanullah Gurbaz (60 off 49) and Ibrahim Zadran (51 off 48) had built a mountain too big to climb with the largest opening partnership ever recorded against Australia in T20s (118 runs).
Afghanistan could smell victory when Maxwell clipped player-of-the-match Gulbadin Naib (4-20) to Noor Ahmad at backward point, consigning Australia to 6-106 in the 15th over.
No other batter reached double figures after Maxwell was dismissed, Afghanistan piling pressure on Marsh's side with their first-ever defeat of Australia.
"It becomes really clear now, we just need to win," Marsh said ahead of the crunch clash with India.
"There's no better team to do it against, one of the biggest challenges in world cricket.
"We'll remain positive, we had an off night tonight, absolute full credit to Afghanistan, I thought they were brilliant. We move on pretty quickly."
Afghanistan's historic victory keeps their own hopes of a fairytale semi-final berth alive ahead of their match against Bangladesh.
"It's a massive win for us as a team and as a nation, in the World Cup, beating champions, it's a great feeling," said Afghanistan captain Rashid Khan.
"I'm super proud of the guys."
Two of Australia's five dropped catches came in the hunt for a wicket to break the blistering opening stand.
As Gurbaz and Zadran wreaked havoc, Matthew Wade missed an easy opportunity for a stumping and Australia twice leaked fours following misfields from Ashton Agar - called in for Mitch Starc.
After dropping an earlier chance, Marcus Stoinis (1-19) had a long-overdue breakthrough when Gurbaz picked out David Warner at deep backward square leg.
Australia's best two front-line bowlers this tournament, Adam Zampa (2-28) and Cummins ensured Afghanistan's batting order never clicked back into gear after that.
Cummins became the first player to record hat-tricks in consecutive T20 games when Gulbadin (0) pulled him to Maxwell at deep midwicket in the final over.
He could've had another scalp off the next ball had the usually reliable Warner held onto Nangeyalia Kharote at deep point.
Naveen-ul-Haq (3-20) vindicated Afghanistan's decision to start with pace, swinging the ball into Travis Head's middle stump with the third delivery of the innings.
The losses of Head (0) and Mitch Marsh (12) inside three overs raised the alarm, and Australia were officially in panic mode when Afghanistan injected spin for the first time.
David Warner (three) skied Mohammad Nabi (1-1) to short fine leg on the off-spinner's first delivery and set the stage for Maxwell to haunt Afghanistan again.
But when the allrounder's gutsy knock came to an end, Australia were into the bowlers and limping to the finish.
With Australia requiring 24 runs from the final over, Azmatullah Omarzai sealed victory when Zampa hit him to Nabi at long on.
