Windies needed 11 runs off the last over but Starc bowled five consecutive dot balls before conceding a six on the final ball to secure a four-run win for Australia.
Australia was cruising to expected victory at 70-3 when it lost six wickets for 19 runs to lose the match by 18 runs
Wiaan Mulder took three wickets for one run to wrap up the tail as South Africa bowled out West Indies for 149 in exactly two sessions.
The West Indies finished 142-4, chasing down Australia’s total 141-6 with 31 balls to spare in the third of five T20s.
Catch the match and team details of West Indies vs Australia first T20 match in St Lucia
Kagiso Rabada finished with 5-34 for South Africa in the second innings, while Roston Chase provided lone resistance for West Indies with his 62.
'Universe Boss' Gayle reached the milestone during his match winning 38-ball 67-run knock for West Indies against Australia in the third ODI
Kagiso Rabada took 5/34, while Quinton de Kock scored 141 as South Africa beat West Indies in under three days. Catch the highlights here:
Catch the highlights and updates of Day 2 of the 1st Test match between West Indies and South Africa here:
Catch the highlights and updates of Day 1 of the 1st Test match between West Indies and South Africa here
Markram was out for 60, while Rassie van der Dussen was 34 not out as South Africa finished at 128-4 at stumps