Central Coast produced an amazing late comeback and dealt a blow to Sydney FC's finals hopes with a 2-2 draw in Gosford.
Teenager George Blackwood and veteran Shane Smeltz each scored in Saturday's first half, but Sydney's streak of matches without a win stretched to nine to leave them in seventh spot with three rounds remaining.
Leading 2-0, Sydney had plenty of chances to kill off the game before half-time against a Mariners side that was still without a clean sheet after 24 matches.
Irishman Roy O'Donovan ended the Mariners' goal drought of almost seven hours with an 86th-minute effort and defender Harry Ascroft equalised in stoppage time, with his shot from outside the penalty area squirming through the hands of Sydney goalkeeper Vedran Janjetovic.
Lively 18-year-old Blackwood notched his first senior goal in his ninth start when his fierce 11th-minute right-foot shot from outside the area took a slight deflection off the Mariners' Liam Rose.
Smeltz latched on to a quickly taken free-kick by impressive midfielder Brandon O'Neill in first-half stoppage time, then cut inside and curled an exquisite left-foot shot past goalkeeper Paul Izzo.
Sydney dominated the first half-hour, but the Mariners had a good spell just before half-time.
They were possibly unfortunate to have a 43rd-minute effort from O'Donovan ruled out for offside.
O'Donovan was denied just after the break by a smart save from Janjetovic, and Josh Bingham had three second-half efforts.
Sydney had chances to increase their lead, with Ascroft making a sensational goal-line clearance to deny Smeltz a second, while Mickael Tavares had a strong shot saved by Izzo.