With a 2-0 lead at half-time, Alex Brosque extended his side's advantage early in the second half before Adelaide rallied for a goal of their own, but the gulf in class was ultimately as clear as the high-definition, 277 square metre Daktronics superscreens towering over the pulsating Cove at one end, and the forty or fifty strangers in red shirts gathered at the other, as Christopher Naumoff scored in injury time to end hopes of a late comeback.
![]() |
Adelaide, for their part, were content to sit back and attempt to hit their opponents on the counter as they have done all year, but did so at the expense of all attacking momentum as Sydney won early corners, and had the first few shots.
The visitors' best chances came from Sydney giving up possession in midfield, and a string of painfully soft free kicks along the sidelines.
Having set the precedent of blowing his whistle whenever he felt like it early on in the match, it was harder to find fault with Ben Williams' refereeing as the game progressed, as he became, increasingly, not so much a good referee making a series of poor decisions as poor referee making a series of decisions that were consistent with his standard of officiating.
After 15 minutes, Sydney had the ball in the back of the net when Janko prodded the ball past Eugene Galekovic in the Adelaide goal, but Williams again called play back for a foul – correctly, this time, for the offside Janko, but it didn't stop the growing dissent in the crowd.
Sydney weathered what amounted to little more a sun shower, and deservedly went ahead in the 18th minute when Bernie Ibini slammed a shot into the roof of the net from the edge of the penalty area; the on-loan Shanghai Dongya striker scoring his seventh goal of the season.
Vedran Janjetovic stood up well to a one-on-one with Sergio Cirio shortly afterwards to keep Sydney ahead, the Spaniard unable to capitalise on Adelaide's best chance of the half.
Adelaide were dealt a sucker punch with halftime approaching as Ibini found himself in space on the right, whipping a low cross towards the near post for Alex Brosque, who flicked the ball behind his standing foot and under a sprawling Galekovic.
It was a goal that stunned the ground into silence, if only for a fraction of a second, before the crowd gathered up the pieces of their freshly-blown minds and exploded into noise.
The second half began as the first had ended, with Eugene Galekovic picking the ball out of the back of his net as Graham Arnold grimaced his way through a celebration on the sideline.
Marc Janko, offside by a hair and a bomb threat when he received a pass inside the Adelaide penalty area, lost possession after running into Nigel Boogaard, but the ball spun fortuitously out of the tackle for Alex Brosque, who swiped his volley home for his second of the night, and his side's third.
As his players rushed past him to celebrate the goal that effectively sealed the win, Arnold’s face seemed to drop to another level of sunken weariness with the world; aggrieved, perhaps, that Adelaide hadn't conceded a penalty and been awarded a red card. He could hardly complain with the resulting goal, but seemed to find reason to do so regardless.
From there, the match began to grind towards its inevitable conclusion: Sydney were happy enough to let Adelaide enjoy a wholly pointless period of possession after the goal, safe in the knowledge that while a two-goal lead is famously the most dangerous score in football, a three-goal lead held by a semi-competent team in the 50th minute of a match is pretty much impossible to overcome.
With the ball, the visitors proved as toothless in attack as they had been in defence, and continued to resort to the long ball as they looked to move play past the Sydney midfield.
Sydney nearly scored the goal of the season in the 70th minute but didn't, and Adelaide broke quickly up the other end to found themselves three-on-three with the Sydney defence.
Craig Goodwin ran the ball towards Matthew Jurman, cutting inside the defender and putting Adelaide on the scoreboard with a shot that deflected off Janjetovic's hand and dribbled at an agonising pace into the goal.
On the sideline, Graham Arnold breathed the sigh of a man who knew how capable his side were of snatching defeat from the jaws of victory.
With nearly 20 minutes remaining, and Adelaide suddenly awake, Sydney's certain victory looked decidedly less certain.
Adelaide began to do that thing that doomed teams usually do when faced with defeat, and decided to try to make the game interesting when it was clear a comeback was beyond them.
They pushed forward in search of another goal, hitting long passes deep into Sydney territory, but the home side's backline held its shape and dealt with every aerial assault from the wings.
A late chance for Cirio went begging; the striker smacking a header over the crossbar from a few metres out in front of goal.
Arnold wheeled away holding his head, and Josep Gombau's jaw clamped down on his fist; both managers largely disappointed with their team's second half performances.
Throughout the second half Sydney had threatened the goal that would kill off the Adelaide resistance, and it came in the 90th minute when Naumoff stroked a shot past Galekovic on the right side of a Sydney break, before turning to dive into the Cove behind the advertising hoardings.
A fifth, as much as the crowd might have wanted it, was a stretch too far, and perhaps would have been an unfair reflection of a match that Sydney deserved to win, despite being on the back foot for much of the second half.
Adelaide's season ends here, while Sydney goes on to Melbourne next week to face the Victory in the final after Kevin Muscat bullied his team into a 3-0 win over local rivals Melbourne City on Friday night.
Sydney FC starting XI: Janjetovic (GK), Petkovic, Faty, Jurman, Ryall, Naumoff, Dimitrijevic, Taveres, Ibini, Brosque (C), Janko
Sydney FC substitutes: Necevski, Grant, Smeltz, Stambolziev, Antonis
Adelaide United starting XI: Galekovic (GK), McGowan, Boogaard, Elrich, Carrussca, Isaias, Malik, Jeggo, Cirio, Sanchez, Goodwin
Adelaide United substitutes: Izzo, Palanca, Mabil, Watson, Marrone