After Ellyse Perry struck 70 off 46 balls to take Australia towards a competitive total at North Sydney Oval, Litchfield hit out late with an unbeaten 52 from 19 balls.
The 20-year-old's knock equalled New Zealander Sophie Devine's record from 2015 for the fastest in women's T20 history, after bringing up her half-century in 18 balls.
Some of Litchfield's stroke-play was incredible.
She hit three sixes, including one off Aaliyah Alleyne when she jumped down the wicket and flicked the ball off her hip and over a wide fine leg.
Litchfield also cleared the rope after hitting a length ball down the ground from pace bowler Chinelle Henry.
Her runs came as she put on 66 from the final 22 balls in a partnership with Georgia Wareham that helped Australia to their highest T20 total against the West Indies.
Wareham also finished unbeaten on 32 off 13.
Australia found themselves in early trouble when Alyssa Healy was caught one-handed by a leaping Shemaine Campbelle at backward point off the first ball of the game.
Tahlia McGrath was bowled for four in the next over by Hayley Matthews (3-36), leaving Australia 2-7.
A 70-run stand between Beth Mooney and Perry allowed Australia to steady the innings.
Perry then took charge, hitting five sixes in her knock after taking a particular liking to spinner Karishma Ramharack.
The veteran right-hander looked on track for her maiden T20 international century before she was caught at long off trying to hit out against Shamilia Connell.
A win will wrap up the three-match series for Australia, after an eight-wicket victory to start the summer on Sunday.
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