Central Coast Mariners recorded their first win of the National Youth League season with a hard-fought 1-0 victory over Sydney FC at Leichhardt Oval on Saturday.
It was also Sydney's first loss of the season following an opening draw against Adelaide United and an impressive victory over Melbourne Heart last week.
The home side fielded Hyundai A-League regulars Shannon Cole and Dimitri Petratos, while Mustapha Amini continued his return from long-term injury with a full game for the Mariners.
Sydney struggled to find the fluency and latitude they did seven days earlier at the same venue when they recorded a 5-1 win against the Heart.
The well-organised and hard-working Mariners proved to be good value for their win, with the difference on the scoreboard being a lone strike early in the second half from half-time substitute Kwabena Appiah-Kubi.
The Mariners turned in a strong first half creating a number of dangerous moments in the Sydney goalmouth, with the tone set inside the opening 30 seconds as Justin Hayward was denied a goal only by a smart save from alert Sky Blues goalkeeper Ryan Norval.
Skipper James Oates saw a powerful header blocked, as did Nicholas Littler soon after, with Trent Sainsbury's follow-up shot blocked by some desperate Sydney defending.
The decisive moment of the match came nine minutes after the interval with speedy frontrunner Appiah-Kubi advancing on goal and finishing at the second attempt after his initial effort was blocked.
The home side were not without their opportunities, perhaps the best falling to Joel Chianese who blazed over when through on goal under pressure, while Caleb Rufer also fired over with an awkward chance from close range.
Much focus was on Amini with the Qantas Young Socceroo star turning in a hard-working performance.
Amini had several second-half strikes from distance but was unable to extend the Mariners' advantage.
Sydney FC 0
Central Coast Mariners 1 (Appiah-Kubi 54)