Ezi Magbegor was inspirational in the victory, recording 27 points and ten rebounds (her third double-double of the tournament) in a thrilling battle with 205cm Chinese centre, Xu Han.
Xu had the better of the battle through the first half, tallying a double-double herself inside 15 minutes of game-time but as she tired down the stretch, Magbegor went to work.
With China threatening to pull away and get their running game going on some fast-break opportunities deep in the third period, Magbegor stood in their way to score six points in the last two minutes.
That pushed Australia in front by three at three-quarter time but Magbegor was not done, taking complete control at the offensive end with six more points and an assist on the Gems' first four possessions of the fourth quarter.
China had one last response, cutting the margin to six inside the final two minutes with some nice three-point shooting but Magbegor and Australia would not be denied with the centre adding four more points on a couple of strong moves in the post before Abby Cubillo (four points, five rebounds) sealed the victory from the free-throw line.
While Xu began the game on the floor for China, the Gems showed no signs of intimidation with Jazmin Shelley and then Rebecca Pizzey (four points, four boards) attacking the rim from the start.
That aggressive style of play gave them a slim three-point advantage at the first change but China responded with a 12-2 run to start the second period as Xu grabbed her double-double.
Chloe Bibby (11 points, three assists) was able to halt the momentum though and then Monique Conti (five points, six assists, three steals) set up Shelley (nine points, five assists) from distance before draining a three herself to bring the Gems within two at half-time.
Taking over the starting point guard role due to an arm injury to Maddison Rocci, Conti continued her impressive play as she racked up assist number six early in the third quarter to give Australia the lead once again.
Turnovers began to creep into Australia's game though and a couple of telegraphed passes gifted China fast-break points as they got into their cherished running game.
However, after spending the first half on the bench, Zitina Aokuso (seven points, three rebounds) was able to bring the hustle back into the Gems' game and on the back of three free-throws, Australia were right in the contest.
Her presence on the floor also freed up Magbegor in the front court and as she found her rhythm following a couple of made baskets, the Gems grabbed a lead which they would not surrender again.
Find the box score here and watch a replay of the game vs. China below.
The Gems will now play the winner of France/Spain for fifth place at the FIBA Under-19 World Cup which would continue a run of finishing into the top five over the past six tournaments dating back to 2007.
That game is scheduled for 12.00am midnight AEST Monday (Sunday night). Stay tuned to Basketball Australia's social media channels for a link to the live-stream.
Australia's Schedule for the Under-19 Women's World Championships (all times AEST):
July 31: Classification 5-6 vs. France/Spain at 12.00am