Pakistan has kept alive its dream of becoming the first side to retain the ICC U/19 World Cup, but has ended Australia's hopes of victory with a 163-run win in the second Super League semi-final in Colombo.
Australia had reduced Pakistan to 5-80 at one stage, but Safaraz Ahmed's side reached 9-287 thanks to a record sixth-wicket stand of 160 between Riaz Kail (84) and Ali Asad (69).
Pakistan then routed the Australians for 124.
The win has propelled Pakistan into the Super League final on Sunday where it will face arch-rivals India.
"That was really disappointing as it was absolutely our worst performance of the tournament after we played lots of good cricket," Australian captain Moises Henriques said.
"We started well but deteriorated in the field and never came back from there but it has been a big learning curve and as long as we walk away knowing we have learnt something then we will be better off."
Henriques (3-57) and Adam Ritchard (2-71) made life tough for the early Pakistani batsmen, coupled with brilliant work in the field that had their opponents on the back foot.
Opener Nasir Jamshaid (15) was brilliantly stumped down the leg-side by Matthew Wade off Ritchard and when Rameez Raja (28) was run out looking for a second run to deep point it seemed Australia had one foot in the final.
But Kail and Asad had other ideas as the ball stopped moving and the fielders tired in the baking humidity, the pair found their feet and played with real fluency.
Australia, requiring almost a run-a-ball right from the start of their innings, found the going tough in the face of Pakistan's impressive opening attack.
The left-arm pacer Jamshaid Ahmed (2-17) swung the ball and removed Tom Cooper (1) and Henriques (8) while Anwer Ali Khan bowled his ten overs straight through and finished with a very tidy 0-45.
Usman Khawaja battled away for 59 from 69 balls but Australia gradually fell further and further behind the required rate and in the face of that mounting task and the increasing pressure they folded.
The last seven wickets fell for just 25 runs as Syed Imad Wasim (3-16) and Muhammad Usman Malik (3-17) wrapped things up with haste.
Meanwhile, a man of the match performance from all-rounder Patrick Ochan has helped Uganda to its first victory of the tournament and sent Scotland home without a win.
Ochan's 64 – the first fifty by a Uganda batsman in the tournament – together with his 3-29 gave his side a 69-run win in the Plate Championship play-off final on Friday.
Uganda reached 9-214 after being sent into bat by Scotland captain Kasaim Farid and then bowled their opponents out for 145.
Pakistan 9-287 (50 overs, Riaz Kail 84, Ali Asad 69)
Australia 124 (32.3 overs, Khawaja 59)
Uganda 9-214 (50 overs, P.Ochan 64)
Scotland 145 (40 overs)