Mitchell Starc held his nerve at the death to guide Australia to their maiden win of the T20I Series by four runs after the West Indies almost blasted their way to victory from an improbable position on Thursday.

Chasing 189-6, the West Indies needed 57 from 24 balls with five wickets left after Mitch Marsh took two wickets in an over, before fireworks from Fabian Allen (29 from 14) and Andre Russell (22* from 13) turned the game on its head in St Lucia.

The pair combined for four sixes from five balls in the penultimate over from Riley Meredith, needing 11 off the final over but Starc sent down five dot balls to Russell in the last to earn Australia a win which makes the series 3-1.

Australia captain Aaron Finch had won the toss and elected to bat, starting strongly with the skipper making 53 from 37 balls alongside Mitch, who top scored with 75 from 44 deliveries, in a 114-run stand.

The tourists stumbled in the middle order again, losing 40-5 with Hayden Walsh taking three wickets, before some late hitting from Dan Christian and Starc lifted them to a strong total.

The West Indies flew out of the blocks in their pursuit with Lendl Simmons posting 72 from 48 before the outstanding Marsh (24-3) dismissed him, along with Nicholas Pooran in quick succession.

All seemed lost for the hosts at 132-5 but Allen and Russell offered hope, before Starc's clutch final over.