Samoa produced their best performance of the IRB Junior World Rugby Championship on Tuesday night, leading at half-time against in-form South Africa before eventually falling 21-8.
Discipline again proved costly, with one player sent to the sin bin in either half.
The Baby Manu were poised to deliver a massive upset while leading 8-7 with 17 minutes remaining before conceding two late tries.
New Zealand coach Chris Boyd, who saw his team sneak into the semi finals after results fell their way, says Samoa have been impressive over the past week.
"Samoa have probably been the over-achievers in this tournament - I think they've been fantastic and they pushed up for a long period of time, beat Scotland obviously and then did really well against South Africa. So they can be pleased with their tournament, which I think is fantastic for our Island neighbours."
Lemalu Semo Sititi's side will next face Australia in a playoff for fifth to eighth place.
Fiji will take on Argentina for ninth to 12th place, after being outclassed 38-0 by Ireland in Pool B.