Glory missed out on the opportunity to move into the top six as they were downed 2-1 by Adelaide United at Coopers Stadium on Saturday.
Andy Keogh's fifth goal of the season gave Kenny Lowe's men an early lead, but the Reds hit back later in the first half via an unfortunate own-goal from Dino Djulbic and a composed finish from Nikola Mileusnic.
Diego Castro went close for Glory several times in the second half, but despite applying some concerted late pressure that had the home defence creaking, the visitors were ultimately unable to secure a share of the spoils from what was an entertaining clash.
The defeat, Glory's first in five visits to Coopers Stadium, sees them remain in eighth spot, while the Reds climb into the top four.
The visitors could hardly have made a better start as Keogh broke the deadlock with the first chance of the game.
Chris Harold and Scott Neville combined to great effect down the right, with the latter then standing up an inviting cross for the Glory skipper who finished with a clinical header.
The lead lasted just seven minutes, however, as the Reds responded via the luckless Djulbic.
Ryan Strain's cross from the right was directed towards George Blackwood and in his attempt to prevent the home striker from reaching it, Glory's recent recruit inadvertently sent a diving header past Liam Reddy and into the far corner of the net.
It was United who remained on the front foot for much of the first half, with Reddy forced into action to foil both Ryan Kitto and Blackwood at close range, but there was nothing the Glory 'keeper could do to prevent the hosts from hitting the front on 37 minutes.
Skipper Isaias provided the defence-splitting through-ball and Mileusnic raced in on goal before calmly slotting home his third goal of the season.
Castro then threatened for Glory early in the second half, dragging a low shot off target from the edge of the box after the home defence had backed off.
The Spaniard also almost teed up Chris Harold just short of the hour-mark, whipping in a low free-kick which the winger met at the near post only to see his toe-poke flash wide.
And although the Reds continued to enjoy the bulk of the possession, Glory created another chance on 68 minutes when substitute Jacob Italiano provided a shooting chance for Castro but his shot was comfortably gathered by Paul Izzo.
Reddy duly matched his counterpart by keeping out a fierce strike from Kitto at his near post before the visitors were denied a possible penalty when the ball appeared to strike Strain's arm as he blocked another effort from a grounded Castro.
Deep into stoppage-time, Italiano came agonisingly close to salvaging a point for the WA side, but his header from a deep Castro cross flew the wrong side of the post.
Glory's next fixture is in a fortnight's time when they face Wellington Phoenix at Westpac Stadium.
Hyundai A-League Round 19
Adelaide United 2 (Djulbic o.g. 12', Mileusnic 37') Perth Glory 1 (Keogh 5')
Coopers Stadium, Adelaide
Referee: Chris Beath
Assistant Referee 1: Matthew Cream
Assistant Referee 2: Paul Cetrangolo
Fourth Official: Alex King
Video Assistant Referee: Craig Zetter
Adelaide United: 20.Paul IZZO (gk), 7.Ryan KITTO, 8.ISAÍAS (C), 14.George BLACKWOOD, 17.Nikola MILEUSNIC, 19.Ben GARUCCIO, 22.Ersan GÜLÜM (2.Michael MARRONE 85'), 23.Jordan ELSEY (5.Taylor REGAN 60'), 24.Jordan O’DOHERTY (16.Nathan KONSTANDOPOULOS 85'), 29.Ryan STRAIN, 37.Daniel ADLUNG
Substitutes not used: 1.Daniel MARGUSH (gk), 25.Apostolos STAMATELOPOULOS
Yellow cards: Adlung, Kitto
Red cards: Nil
Perth Glory: 33.Liam REDDY (gk), 3.Marc WARREN (2.Alex GRANT 58'), 4.Shane LOWRY, 7.Joel CHIANESE (6.Mitch NICHOLS 54'), 8.Xavi TORRES, 9.Andy KEOGH (c), 14.Chris HAROLD (26.Jacob ITALIANO 67'), 17.Diego CASTRO, 23.Scott NEVILLE, 66.Dino DJULBIC, 88.Neil KILKENNY
Substitutes not used: 13.Nick FEELY (gk), 15.Brandon WILSON
Yellow cards: Torres, Warren
Red cards: Nil