Afghanistan captain Rashid Khan can finally look forward to sleeping better after Saturday's T20 World Cup win avenged last year's loss to Australia in the 50-overs version.

Cramped-up Glenn Maxwell's incredible double-century helped Australia snatch victory from the jaws of defeat in November, leading to Afghanistan falling just short of qualifying for the semi-finals.

But a 21-run win in Kingstown, Afghanistan's first in the Super Eight stage, has reignited their hopes of making history by qualifying for a World Cup semi for the first time.

"I can sleep better now, I think," Khan told reporters. "That game kept coming in my mind ... Maxi, the way he played that night, took the game away from us and I didn't sleep the whole night.

"Tonight, because of the happiness I won't be able to sleep. That's how happy the whole team is and the whole country is. It's a massive win for us, as a team, as a nation.

"Cricket is the only source of happiness back home, we all know that. And I feel like we are so lucky to be here giving happiness to the people back home."

Afghanistan, third in Group One with two points and trailing Australia on net run rate, have a shot at finishing in the top two and making the semis if they beat bottom side Bangladesh on Monday when Australia play leaders India, who have four points.

"Yes, tonight we had an off night but I guess there's also a positive in the fact that in 36 hours we go again," Australia captain Mitchell Marsh said. "It's a big game, it will be against India obviously and it's a must-win game.

"I think if you look back at the short history of this team, I know for a fact that it brings out the best in our guys, so the boys will certainly be up and about for it."