The Matildas will meet the Japanese at Sydney's Stadium Australia on Saturday after Asian football's superpower made light work of the Koreans at the same venue on Wednesday evening.
Nils Nielsen's side gave a clear snapshot of why there is a gulf between Japan and the rest of the continent as they ran out to a 2-0 half-time lead in front of 17,367.
Japan had 64 per cent of possession and nine shots on target, restricting a Korean side that drew 3-3 with the Matildas at the group stage to just three strikes.
"I think it was a very optimistic performance and we tried to take a step up from the level we have shown so far," Nielsen said.
"It's going to be a battle and I am hoping we can beat them (Australia).
"Joe (Montemurro) is a good friend of mine and I'm full of admiration how he managed to get the team to the final with the obstacles that he's had."
On the evidence available throughout this tournament and in Wednesday's showing - Japan have scored 28 goals across five games - Montemurro's Matildas side will have their work cut out.
Japan pressed and hurried South Korea with a brutal intensity that left the Taegeuk Ladies looking increasingly disorganised in a first half where they also had two goals chalked off by VAR.
South Korea seemed to spend an eternity camped in their own half as Japan hassled them into coughing up possession and eventually the game's first goal.
Kim Shinji was dispossessed inside her own box in the 16th minute and Fuka Nagano was able to square the ball for Riko Ueki to finish.
Ueki leapfrogged Australia's Alanna Kennedy in the golden boot standings with her sixth strike of the tournament.
Even with an early lead, Japan didn't take their foot off the gas and they doubled their advantage when Maika Hamano slipped the attention of two Korean defenders on the right.
Hamano drove towards goal and unleashed a shot that beat South Korean goalkeeper Kim Minjung at her near post. But Shin Sang Woo's side were unable to conjure up a response when it mattered in the second half.
Defender Saki Kumagai headed in a corner with a quarter of an hour left to rubber stamp victory for Japan.
Kang Chae Rim clawed one back for Korea in the 78th minute and became the only player to score against the Japanese at this tournament.
But Remina Chiba quickly restored a three-goal buffer that killed off Korean hopes and set up a showdown with the Matildas.
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