Ange Postecoglou and his Socceroos came back down to earth with a bump on Saturday, going down to the Taeguk Warriors and leaving themselves with a tougher route to the final.
Front three rested
With hot, humid conditions in Brisbane set to drain the players and only a draw needed to secure top spot in Group A, Ange Postecoglou picked a starting XI that prioritised the knockout stages.
Losing the game at Suncorp Stadium was seemingly less of a concern than having key players fit and firing for the quarter-final, irrespective of the opposition.
But with a tougher route to the final now awaiting them, beginning with China in Brisbane on Thursday and a followed by a potential semi-final against Japan in Newcastle, could the decision ultimately backfire?
Suspended Spiranovic will be missed
Western Sydney Wanderers FC centre-back Matthew Spiranovic, the lynchpin of the Socceroos' defence, will sit out the quarter-final in Brisbane on Thursday after picking up his second yellow card of the tournament.
Forced to bring down his man with Australia caught on the counterattack, his distribution and calm assurance at the back will be sorely missed against China.
Alex Wilkinson is certain to come in alongside fellow former Central Coast Mariner Trent Sainsbury. Wilkinson had been a regular under Postecoglou until this tournament, acquitting himself reasonably well at the World Cup in Brazil.
Having already taken off James Troisi for Mathew Leckie, introducing forward Tim Cahill in place of midfielder Matt McKay appeared a bold switch at first inspection, but it left the Socceroos top heavy and with only Massimo Luongo to create chances behind the front line.
Kruse did his best to run at the tiring South Korea defence, missing one golden chance to equalise.
But both he and Leckie found their opportunities to drive at the opposition limited, with Uli Stielike's men sitting deep in two banks of four.
Juric and Cahill were left feeding off scraps, well-marshalled by the Taeguk Warriors' unflappable centre-back duo.
Perhaps keeping Troisi on or introducing the experience of canny playmaker Mark Bresciano would have equipped the hosts to better exploit their dominance of possession against exhausted opponents.
Juric battles gamely
After impressing off the bench and scoring against Oman in the second match of Group A, the Wanderers striker - during a week in which he reportedly rejected a big-money move to China at the last minute - was afforded a start by Postecoglou and gave it his all in Queensland.
The 23-year-old got little change out of the South Korean defence though, twice failing to hold the ball up with his back to goal, as imposing centre-back Kwak Tae-hwi outmuscled him with relative ease.
Cahill didn't fare any better when he came on late in the content and there will be plenty more chances ahead of Juric, but it was an opportunity to make a statement missed by the confident youngster, who should have equalised from close range in the second half.
Price paid for a defensive lapse
The men in green and gold and their supporters were riding on the crest of a wave after two convincing wins in the opening two matches, but on Saturday they received a painful reminder of the potential cost of switching off for even a split second against elite opponents.
Three players were sucked into the man in possession, Ki Sung-yueng, during the lead-up to South Korea's only goal, leaving the space for the Lee Keun-ho to run into and deliver what proved to be the killer blow.
There were few other such worrying moments at the back in this one, Ryan on one occasion late on was required to make himself big and prevent Stielike's men from finishing it off on the break. There was also a let off early in the first half, Kwak rising above Luongo and narrowly failing to head his team into the lead.
Set-piece defending and concentration in the defensive third have been Australia's undoing on several occasions throughout Postecoglou's tenure and until those issues are eliminated the Socceroos will remain vulnerable, regardless of how good they look going forward.
The Socceroos will face China PR in the Quarter-Finals of the AFC Asian Cup at Brisbane Stadium on Thursday 22 January (8.30pm local kick off). Click here to purchase tickets.