The Australians were left with a must-win contest after losing their second match to Sri Lanka on Monday and West Australian Wyllie again obliged in the St Kitts and Nevis capital Basseterre on Wednesday, anchoring them to a seven-wicket victory with his unbeaten 101.
It was an accomplished follow-up to the 17-year-old opener's excellent effort in the first match against their West Indies hosts last Friday, when his 86no led to another successful chase in their six-wicket victory.
Yet this innings was even more satisfying with Wyllie knowing that nothing but victory would be enough to keep Australia in the hunt for a place in the eight-team Super League section of the competition.
If Sri Lanka beat West Indies in Basseterre on Thursday (Friday AEDT), Australia's passage will be assured but if the result goes the other way, it will still come down to net run rate, with only two of the three progressing.
Chasing 8-236, the Australians made their target with 61 balls to spare, and Wyllie was able to bring up his hundred in the 39th over with a six before a boundary from Isaac Higgins in the following over sealed the win.
In all, the Mandurah teenager faced 115 balls for his unbeaten 101, hitting eight fours and two sixes.
Wyllie and Campbell Kellaway (47) set a solid base with their 101-run opening partnership but the real impetus for a swift victory came when Wyllie was joined by 18-year-old Aidan Cahill, who smashed 72 off 45 balls, including four sixes.
Cahill dominated their second-wicket partnership of 97 before he was bowled in the 33rd over, but his fireworks did enough to make life straightforward for Wyllie, whose obvious promise has already been demonstrated with a century for Western Australia second XI.
Cahill had earlier also taken 2-33 off his five overs as paceman Will Salzmann was instrumental in stifling the Scots with his 2-39 off nine overs while both Charlie Tear and Tomas Mackintosh scored fifties in a losing cause.
