In their second game, Australia earned themselves an early night by chasing Ireland's total within 10 overs, riding on an onslaught from Alyssa Healy who scored the fastest fifty in ICC Women's World T20 history, and the second fastest in all T20Is.
India chased the target of 135 runs in the last ball of 19th over.
Courtesy the victory, India (with four points) now have one foot in the semifinals from the five-team Group B.
India also avenged their narrow 2-run defeat under D/L method against Pakistan in New Delhi in the previous edition of the tournament in 2016.
Earlier, Ireland had won the toss and batted, and had two major partnerships: 27 at the top and 41 for the sixth wicket, but precious little in between.
From then Bismah Maroof and Nida Dar put together a record-breaking partnership that took Pakistan to their highest ever T20I score. Sent to open, Raj took her time and later accelerated playing some aerial shots as India coasted to a comfortable win against arch-rivals Pakistan. Elysse Perry accounted for two wickets in four overs and gave away just 12 runs. All the three were regulation catches.
Dar was dropped on 15 and again on 29, and Maroof enjoyed some good fortune on 28 when a gentle top-edge spooned over the umpire's head but was allowed to drop to the ground after bowler and fielders left it to each other. Poonam Yadav too dropped Dar in the 13th over when she was on 23.
Maroof (53 off 49) and Dar (52 off 35) made the most of it, taking on the bowlers in a 94-run stand. India did well to pull things back at the finish, keeping the opposition to 133/7.
INDIA 137 for three off 19 overs (Mithali Raj 56, Smriti Mandhana 26).
The Pakistani duo began to hit boundaries at regular intervals and both reached to their fifties towards the end of the innings.
She took full advantage, soon reaching her seventh T20 worldwide fifty.