Townsville: Australia enter into the final of the ICC U19 Cricket World Cup after defeating South Africa by four wickets in Townsville on Tuesday.
After winning the toss and electing to bowl first Aussies' bowlers restrict Proteas to 191 for eight from its 50 overs.
Cameron Bancroft (65) and Kurtis Patterson (49) then impressed with the bat to help Australia seal victory with nine balls to spare as they finished at 192 for six.
Australia opener Jimmy Peirson (duck) caught behind from just the second delivery of the run chase.
Peirson was caught off a lifting ball from the impressive Lizaad Williams (3-40) and in the next over, Meyrick Buchanan (0) was bowled when he tried to leave a Corne Dry (1-40) delivery, only to see the ball clip his bat and ricochet onto the stumps.
It was a cruel blow for Australia but brought Patterson to the crease and he got on the front foot immediately, racing to 16 runs - all of which came in boundaries.
Patterson was twice dropped on 28 and 37 off the bowling of Calvin Savage, before a lengthy delay saw him ruled not out after a run out attempt from the South Africans.
Patterson's fortune ran out on 49 though, when he edged Williams to wicketkeeper Quinton de Kock with the score on 98.
Australia captain Will Bosisto (40) strode to the crease and quickly got to work though, adding 75 runs with Bancroft - who was also dropped on 23 off the bowling of the unlucky Savage - in a partnership that lasted almost 17 overs.
Bancroft was eventually run out in the 44th over, and although Travis Head (zero) lasted just two deliveries, Bosisto (40) and Ashton Turner (11 not out) guided Australia to victory.
Earlier, Mark Steketee (3-35) and Joel Paris (1-36) claimed early wickets as South Africa slumped to 37 for three.
With danger man de Kock (one) out in just the second over, the pressure was put on Proteas captain Chad Bowes.
Bowes, who made 46 in a 104-ball stay at the crease, was extremely patient and laid the foundation for a big finish with an 88-run partnership with Murray Coetzee (50).
But the batting powerplay, taken in the 36th over, changed the complexion of the match.
Instead of scoring quickly ahead of the final 10 overs, three wickets fell as the Aussies wrestled control of the momentum.
Steketee - who bowled superbly all day - broke the all-important partnership when he had Bowes caught behind and he added the wicket of Shaylin Pillay (one) shortly after.
Coetzee was run out when Turner threw down the stumps and the economical Gurinder Sandhu (2-23) also bowled well as Australia finished strongly.
Prenelan Subrayen (30 not out) kept the scoreboard ticking over for South Africa in the final stages but they posted a total that was just not enough.
Australia will meet either India or New Zealand in Sunday's final in Townsville.
South Africa Under-19 191 for 8 (Coetzee 50, Steketee 3-35)
Australia Under-19 193 for 6 (Bancroft 66, Williams 3-40)
Result Australia Under-19 won by four wickets
MOM Cameron Bancroft (Australia Under-19s)