Australia’s hopes of qualifying for the T20 World Cup semi-finals are hanging by a thread after Jonathan Trott’s Afghanistan beat them for the first time ever.

Afghanistan, inspired by Gulbadin Naib’s four for 20, stunned Australia by 21 runs in St Vincent, setting up a thrilling final set of matches in the Super Eight stage.

Australia must now down unbeaten India to have any hope of qualification for the last four. Even that may not be enough if Afghanistan beat Bangladesh heavily in their last game of the Super Eight stage. India have beaten Afghanistan and Bangladesh but are not mathematically through to the last four yet either.

“We were waiting [for this] for a long time. It’s a great moment not just for me but for my nation and my people,” said Gulbadin. “[It is a] big achievement for our cricket. I have no words to say but thanks to the fans for supporting our career and cricket journey. It’s great teamwork, we worked hard for the last two months and the result is in front of you.

“Thank god we, at last, beat Australia. It’s a great achievement for our cricket in Afghanistan. If you look at the history of our cricket, it is not much. The last 10 years, we achieved a lot of goals. This is a big achievement.”

Australia captain Mitchell Marsh admitted his team were “outplayed” and Afghanistan’s win was hard fought. Openers Rahmanullah Gurbaz, the tournament’s leading run scorer, and Ibrahim Zadran put on 118 for the first wicket in 16 overs. When they were separated, Afghanistan stumbled to 148 for six on a tricky pitch, with Pat Cummins remarkably picking up a second hat-trick in as many games. On a ground where chasing is notoriously tricky, that looked a good score, and Australia were left to rue an uncharacteristically scrappy fielding display.

Gulbadin was the third scalp of Cummins’s hat-trick, making a golden duck in the final over of Afghanistan’s innings, but before long he was his team’s hero.

Only Glenn Maxwell, whose unforgettable innings ensured Australia beat Afghanistan in Mumbai at last year’s ODI World Cup, passed 12 in the chase. He made 59 from 41 balls, but fell to Gulbadin, who had already picked up the wickets of big-hitters Marcus Stoinis and Tim David. Australia fell to 127 all out.

“It’s a massive win for us as a team and as a nation,” said Afghanistan captain Rashid Khan. “In a World Cup, to beat champions [Australia are 50-over world champions] is a great feeling and it is something we have missed.

“It’s just the beginning for us and we have every chance of making the semis.

“It’s so important for us and back home. People in Afghanistan are badly missing this win and I’m sure they are proud of us.”