South Korea secured top spot in Group A in the 2015 AFC Asian Cup with a 1-0 win against host nation Australia on Saturday in Brisbane to make it three victories out of three for Uli Stielike's side.
Here are three points to come out of the battle of two of the continent's heavyweights:
1. Socceroos shuffle their deck
With a quarterfinal spot already secured for both teams, Australia coach Ange Postecoglou once again gambled by tinkering with a winning side as he made four changes.
Aziz Behich's return at left-back for Jason Davidson was predictable enough. But what wasn't expected was a brand-new front three of Tomi Juric, Nathan Burns and James Troisi, with the talismanic Tim Cahill left on the bench, along with Robbie Kruse and Matthew Leckie, arguably their nation's best performers against Oman.
After Australia made another slow start, the new trio began to jell. Juric, the Western Sydney hero in their 2014 AFC Champions League win, had his nation's first shot on target and missed a close range equaliser in the 53rd minute. Troisi hit the side netting after 36 minutes and showed his ease on the ball as much of Australia's possession came through him, from Mark Milligan and Massimo Luongo.
But Burns, the A-League's top scorer this season, was the standout, especially in the first half as he got behind a new-look South Korea back four.
In the 17th minute his near-post effort was knocked behind for a corner. In first-half injury time, he had a powerful shot blocked from a dangerous position. And just before he was subbed off on 70 minutes, his stinging right-footed effort almost gave the Socceroos a lifeline, only to be parried away.
In his first Australia start in four years, Burns did enough to push for a place in the XI for the quarterfinals.
2. 'Dave's' homecoming in Brisbane
At least two of the midfielders in the Group A showdown felt very much at home in a city that they know well and love.
Brisbane Roar captain Matt McKay was one of them. The other? South Korea captain Ki Sung-yeung who spent four years at Brisbane's John Paul College as a teenager when he went by the name of "Dave" Ki.
The Swansea star was immediately in the thick of the action, breaking up a promising Australian triangle in the ninth minute. Twenty minutes later, he was calling for a red card -- in his excellent English -- when Burns was shown a yellow for using his elbow in a clash with Park Joo-ho.
But the true measure of his class was the pass he threaded into the attacking penalty box in the 33rd minute for Lee Jeong-hyeop to put Korea ahead at half-time. Right-back Ivan Franjic was caught out of position as the 23-year-old striker's shot beat a diving Mathew Ryan.
His influence in the second half was no less as Australia left more space in the midfield as they pushed for the equaliser. His marauding 50-metre run in the 54th minute to set up a promising attack had echoes of Roy Keane about it.
After almost 100 games in English football for Swansea and Sunderland, Ki already looks like he belongs in the Premier League. At this 16th edition of the Asian Cup, he has the swagger of a skipper who knows he has the ability to change the course of any game, whether it's a pass like the one he delivered for the goal, a perfect set piece or forcing a crucial turnover.
3. Tale of two coaches
With Postecoglou winning praise during the group stages of the Asian Cup for sticking to his attacking philosophy, South Korea head coach Uli Stielike had been getting a torrid time from Korean media for his selections and the team's style of football.
Injuries and illness haven't helped -- they forced him to make seven changes for the previous Group B game against Kuwait.
And by the 49th minute, he had to make a second substitution after Koo Ja-cheol, nursing a suspected shoulder injury, was carried off to join Park Joo-ho on the sidelines.
Stielike was frequently on his feet in Brisbane, protesting at Australia's overtly physical style.
But the second change saw the introduction of gifted forward Son Heung-min and the Bayer Leverkusen star was quick to stamp his mark on the game, stretching the Australian defence. Despite not being fully fit, he was probably the standout player of the second half, even though Stielike had probably planned to introduce him later.
Postecoglou waited until midway through the second half to inject the power-packed trio of Leckie, Cahill and Kruse -- the latter is a teammate of Son's at Bayer Leverkusen. From that point onwards, they looked more dangerous on a bumpy pitch.
Brisbane boy Kruse thought he was going to equalise in the 88th minute after working a lovely one-two with Juric only to see Korean goalkeeper Kim Jin-hyeon make one of the saves of the tournament to preserve the clean sheet.
The defeat for Australia means they could face defending champions Japan in the semifinals. Before that, they'll have to overcome China on Jan. 22 without key central defender Matthew Spiranovic, who picked up a late yellow card to earn an automatic suspension.
One understands that by rotating his squad Postecoglou wanted to avoid the kind of burnout the Socceroos suffered in their third group match at the 2014 World Cup against Spain. But this disappointing result could come back to haunt the Asian Cup hosts.