Talented teenager Sam Silvera scored on his first A-League start to help Central Coast to beat Perth 2-1 in an upset at HBF Park.
The 19-year-old's superb solo effort just before half time on Sunday secured the Mariners' first win of the season after drawing their first two outings.
The score was level at 1-1 before Australian youth international Silvera picked the pocket of sleepwalking Glory substitute Jacob Tratt and curled in a superb low finish from a tight angle.
The Glory had plenty of chances to find an equaliser after half time but couldn't convert, to the frustration of the 8,148 crowd. Perth had been strong favourites but looked off the pace all day with vaunted forward trio, Bruno Fornaroli, Diego Castro and Chris Ikonomidis unable to have much impact.
Central Coast had the run of play early and there were danger signs in the opening minutes when Milan Duric found space to unleash a sizzling hard and flat shot which hit the woodwork. Former Glory player Danny De Silva ran on to the deflection directly in front of goal but couldn't bring it under control.
De Silva redeemed himself in the 17th minute when he was on the end of an intelligent cross from Jack Clisby and delivered a pinpoint low finish from the edge of the box.
Perth drew level in the 32nd minute, Juande forcing a great save from Mark Birighitti and Ivan Franjic pouncing on the deflection from close range. The hosts had all of the play in the second half but couldn't break through the Mariners' determined defence.
Glory fans thought they had an equaliser in the 49th minute when Fornaroli fired a volley into the arms of Birighitti but VAR confirmed the Mariners' keeper had not stepped over the goal line.
Substitute Joel Chianese also had a good chance in the 76th minute but was unable to make full connection with his header.
The result leaves the reigning premiers with just one win from their first four games.