Tahlia McGrath has taken the captaincy reins seamlessly from the injured Alyssa Healy to lead Australia into the semi-finals of the T20 World Cup, while also handing big rivals India a potentially fatal blow.

McGrath, taking over because of skipper Healy's foot injury, led from the front in Sharjah on Sunday with a brisk knock of 32 as the champions again demonstrated their enviable strength-in-depth in their nine-run victory.

Halfway through India's chase of the Aussies' 8-151, McGrath's side had already done enough statistically to guarantee qualification.

But the unbeaten side were determined to maintain their stranglehold, restricting India to 9-142 - thanks to four wickets in Annabel Sutherland's last over - to hand their fancied rivals a defeat that leaves their semi-final hopes out of their hands.

If New Zealand beat Pakistan on Monday, India will be eliminated and the Kiwis will advance. Pakistan still have an outside chance too if they win.

Australia's dominance was challenged belatedly by India skipper Harmanpreet Kaur, whose unbeaten 54 not out threatened an unlikely win if they could hit 14 off Sutherland's final over.

But on the day after her 23rd birthday, the allrounder was coolness personified, conceding just five runs while taking two wickets and watching two other Indian batters being run out.

It ensured Australia kept up their record of featuring in the semi-final in every T20 World Cup, while winning a 15th straight match in the competition.

Asked if it was important to maintain their 100 per cent record, McGrath smiled: "Absolutely. We want to win every game we play.

"We knew it was going to be a really big challenge for us today. They came really hard at us, and I am just really proud of the group. We kept our nerve at the end there."

It's uncertain if Healy, who suffered an "acute right foot injury" in Friday's win over Pakistan, will be fit for the knockout matches, with the team saying the 34-year-old "will continue to be assessed and her availability determined in due course."

But on the day quick Tayla Vlaeminck was ruled out of the tournament after her shoulder dislocation and Heather Graham called up as replacement, McGrath proved an able stand-in captain as she beat Meg Lanning's record as the quickest Australian woman to 1000 T20I runs.

After winning the toss and opting to bat, McGrath was into the fray in just the third over after Renuka Singh dismissed Beth Mooney and Georgia Wareham in successive deliveries.

McGrath cracked four boundaries in her 32 off 26 balls while enjoying a 62-run partnership with stand-in opener Grace Harris, who hit 40 off 41 balls.

A sparky mid-innings contribution from Ellyse Perry, who hit one of only two sixes in the innings in her 23-ball 32, was followed by a late cameo from Phoebe Litchfield, who smacked the other off the final delivery to propel Australia past 150 to the highest score by any team at Sharjah in this competition.

Australia suffered from three more dropped catches by Megan Schutt, Sophie Molineux and Darcie Brown, but even Kaur recognised afterwards their otherwise excellent fielding was the key difference between the teams.

The Australian bowlers all contributed superbly, with the miserly Schutt (1-25) having Jemimah Rodrigues caught at deep-midwicket by Ash Gardner (1-32), who herself tempted big-hitting Shafali Verma (20 off 13) to pick out Sutherland at long-on.

Sophie Molineux (2-32) was player of the match after grabbing the key scalps of Deepti Sharma (29 off 25) and Smriti Mandhana (6 off 12), while Sutherland's 2-22 could easily have won her the player of the match accolade.

Her final over amid the excitable din from a hugely pro-India crowd was immaculate as she clean bowled the threatening Pooja Vastraka and trapped Radha Yadav lbw to seal the deal.