A chaotic final five minutes condemned Perth to Champions League heartbreak, as the Glory conceded two late goals to suffer a 2-1 injury-time loss to Ulsan Hyundai.
Youngster Daniel Stynes looked to have etched his name in Perth's history when he handed the Glory the lead in the 71st minute.
The loss is a brutal blow to Perth's hopes of progressing to the knockout stage, as they have zero points from three games and are bottom of group F with three games remaining.
Perth were on the back foot from the outset against the K League powerhouse -- who featured former Glory defender Jason Davidson in their starting line-up.
Ulsan dominated the first half but were consistently met by a resolute Glory defence, with centre-back Jonathan Aspropotamitis particularly desperate.
Kim In-sung hit a chance straight at Perth goalkeeper Tando Velaphi in the 56th minute but from there the Glory remained resolute and found a foothold in the match. Then, Stynes struck. The 22-year-old found space at the top of the area and lashed a low, skidding shot into the bottom corner.
But Richard Garcia's Glory were unable to maintain their advantage and 18 minutes after the opener, Ulsan found their equaliser.
Yoon Bit-garam cleverly controlled a cross and knocked the ball back for an unmarked Kim In-sung to score with a well-placed strike.
Perth's Bruno Fornaroli almost reclaimed the lead in the 90th minute, forcing a superb diving save from Ulsan goalkeeper Jo Su-huk. Then, in the third minute of injury time, Kim In-sung turned provider, looping a clever cross from the left into the path of Junior, who coolly volleyed home the winner.