Travis Dodd's first-half goal has given Perth Glory a 1-0 win over Central Coast that guarantees the Western Australians a place in the A-League finals.
Mariners goalkeeper Mat Ryan made an awful howler midway through the first half to gift Travis Dodd the only goal of a game which was blighted for Perth by an apparent chest injury to captain Jacob Burns.
Dodd's fourth goal of the season, which came after Ryan spilled a simple cross into his path, allowed Glory to take the points and climb into third spot with two games to go after resisting Central Coast's pressure late in the game.
Seventh placed Sydney could still overtake Perth but as they play Melbourne Heart and Newcastle - fifth and sixth respectively - over the final two rounds, there is no way all three can finish ahead of Ian Ferguson's men and knock them out of the top six.
The league leading Mariners, who were largely lacklustre thanks to the mammoth travel load that saw them play in China in the Asian Champions League midweek, now have a gap of just two points over the Roar and face pressure heading into their last two games against Adelaide and Wellington.
The Glory's win did come at a huge cost though, with Burns stretchered from the field in the 52nd minute after copping an elbow to the chest in a collision with Joshua Rose.
Steve Pantelidis and Josh Mitchell also face suspensions against Gold Coast next week after both picked up their fifth yellow cards.
The kick-off temperature of 36 degrees sparked some talk of delaying the start of the match and while that was ultimately rejected, the scorching weather did result in an uninspiring opening until Ryan's 25th-minute catastrophe.
Ryan should have gobbled up a harmless Todd Howarth cross, even though he was looking into the sun, but let it go straight through his hands under little pressure which allowed Dodd to tap in.
But Ryan did go some way towards making amends with a smart save low to his left to deny a Dodd shot from the edge of the box on the stroke of half-time.
Central Coast built promising attacks at times in the first stanza but couldn't convert that final third possession into chances, although they were nearly back level soon after the break when Daniel McBreen drifted free from a set-piece only to head wide from close range.
The Mariners again nearly levelled in the dying stages, only for McBreen's header to be cleared off the line by Josh Risdon, but couldn't make their pressure count and have now won just one of their last seven Hyundai A-League matches.
Perth Glory 1 (Dodd 25)
Central Coast Mariners 0
Crowd: 6502 at nib Stadium, Perth