Kyah Simon got the Matildas off to the perfect start after she poked home inside a minute, with Emily van Edgmond doubling the Aussies advantage from the penalty spot.
Coach Alen Stajcic reverted to the same XI that started the tournament opener against Japan bar Kyah Simon, who retained her spot up front.
The move paid immediate dividends after the hat-trick hero against Vietnam was on hand to apply the finish after a shot from Lisa De Vanna came back off the bar.
The Australian co-captain again provided the assist for Australia's second goal, earning a penalty after she was fouled in the box as she loomed in on goal.
Playing in her 50th international Emily van Egmond stepped up to take the spot kick, making no mistake to give the Aussies a two goal advantage inside 15 minutes.
The win takes the Australians to a maximum nine points after three games, two points ahead of nearest rival China who upset Japan 2-1 to firm up their position in the standings while extinguishing the host's Olympic hopes.
DPR Korea’s last gasp 1-0 win over Vietnam in the other match means the Matildas are still not guaranteed a prized top two finish but Head Coach Alen Stajcic knows they could not have put themselves in a better spot with matches to come against China P.R. and DPR Korea, the two countries looming as the other two contenders.
“We’re in a good position now with three good wins and the players worked really hard for that victory,” said Stajcic.
“I thought it was a really tough game and it could have gone either way. Korea Republic gave us a very good run and they certainly dominated large parts of the game and were maybe unlucky at times but we looked good on the counter attack and we were dangerous when we could get forward and in behind.”
“But full credit to Korea Republic because I thought they were a really good opponent tonight.”
The Aussies were forced to dig deep against a Korea Republic that asked some serious questions throughout the 90 minutes but they held firm and Stajcic said the ability to still come out in front was testament to the squad’s progress.
“I think it’s a sign that this team is maturing now, they’ve hit a period where there is some real growth on and off the field in the group,” said Stajcic.
“To be able to battle out a game like that and probably not be at your best but still dominate patches and be effective shows how far we’ve come and certainly that will hold us in good stead when we are faced with tough battles like that.”
Knowing the importance of the result, Australia could not have asked for a better start as they struck inside a minute. De Vanna was released by a neat through ball and found herself with just the keeper to beat, her shot from the angle rolling off the far post and Simon was quickest to react as she pounced and smashed the ball into the back of the net.
De Vanna was then a key figure as the Aussies extended their lead when she won the foot race with her marker and was felled in the penalty area. Van Egmond stepped up and accurately slotted home the spot kick to give the Westfield a two goal advantage with less than 15 minutes gone.
Korea Republic were lively as they attempted to get themselves back into the game but their momentum was halted on the half hour due to a short delay after captain Cho So Hyun felt the full brunt of a thunderous Elise Kellond-Knight effort from long range.
De Vanna was prevented from adding a goal of her own by the sharp reflexes of Korea Republic goalkeeper Kim Jung Mi in the 38th minute as the Matildas absorbed everything Korea Republic threw at them to hold onto their two goal buffer.
On the hour Steph Catley slid a delightful ball in for substitute Caitlin Foord, the dashing winger producing a clinical finish but the flag was up for offside before Clare Polkinghorne hit a shot just wide of the post in a dominant little period just after the hour mark.
With time running out Korea Republic started to get desperate and would have pegged a goal back in the 80th minute if not for a quality reflex save from Lydia Williams as she tipped over a stinging shot.
Foord had a couple of opportunities to kill the game off in the closing stages but Kim Jung Mi denied her both times, the final whistle signalling another invaluable three points.
The side now gets a two day break before their next match against DPR Korea on Monday (7 March 2016) at Yanmar Stadium (kick-off 7.35pm local, 9.35pm AEDT).
A top two finish in the group will see Australia qualify for August’s Olympic Games in Rio de Janeiro.
Football Federation Australia