With the same starting five as the Quarter-Final, Marianna Tolo and Kelsey Griffin set the tone as they have done all tournament.
Tolo (six points, eight rebounds, three assists, two steals, three blocks) filled up the paint and had a big rejection which worried the Koreans out of entering the key on subsequent plays while Griffin (16 points, nine rebounds, two steals) scored six of Australia's first eight points before drilling another three-pointer to have ten points by quarter-time.
Yung Hui Lim caught fire for Korea though and just when Australia looked like it would be another comfortable victory, the Koreans finished the period on a 13-6 run to trim the deficit to just five at the first break.
The Opals began to take advantage of turnovers in the second quarter, reading their opposition's passes while utilising the skill-set of Alanna Smith (12 points, six boards) in the paint to respond with an 8-2 run.
Mansfield (ten points, four assists) then drained her second three-pointer to force Korea into a time-out but it could not slow down the point guard's momentum as she scored seven straight points for the Aussies.
Her pace seemed kicked the Opals into another gear as they began to push the tempo, even off Korean makes, and that enabled them to get some easy points from the free-throw line where they hit 10-12 as a team through the first half.
Some strong offensive rebounding from Sara Blicavs (ten points, eight rebounds) also gave her team quality second chance looks as they extended their margin to 15 at half-time.
From there, the rigours of a week-long tournament started to take their toll on Korea with injuries affecting a couple of players who were visibly limping up and down the floor.
The Opals also pushed out to a 12-2 edge in offensive rebounds as well but a third-quarter slump, which has reared its head a few times for Australia at the Asia Cup, allowed Korea to again get back into the contest.
They only got as close as 14 though before Katie Ebzery (six points, five assists) settled things down to push the margin out to 20 at the final change.
The fourth term followed a similar pattern as Korea showcased their impressive long-range shooting until Maddie Garrick and Tessa Lavey got on the board to halt any hopes of a miracle comeback.
Korea kept fighting though and a hail-mary on the buzzer was their eighth three-pointer of the game to cut the final margin to 17 points.
Check out all the stats here.
The Opals will now face the winner of China/Japan in the other Semi-Final with the gold medal game scheduled for 12.30am Sunday on Fox Sports channel 503.
The Australian Opals FIBA Women's Asia Cup Schedule (all times AEST):
July 30: Gold medal game at 12.30am vs. China or Japan