Sydney FC started well having the bulk of the early chances on what was a very patchy Allianz Stadium. Alessandro Del Piero was providing good service for his front men but Sydney couldn't beat the Mariners defense.
The Mariners slowly came more in to the match in the midway of the first half but they couldn't create any real chances as they attempted to regain top spot.
Sydney FC responded though and opened the scoring as Seb Ryall picked up a switch of play and hit a powerful shot that deflected off Trent Sainsbury leaving Mat Ryan strained.
The Mariners tried but failed to create any real chances despite dominating the possession after the goal, Sydney FC rarely looked threatened and took a 1-0 lead in to the break.
Less than ten minutes in to the second half Graham Arnold went to the bench and brought on Mitchell Duke for Mile Sterjovski in an effort to find a goal.
In the 56th minute Daniel McBreen nearly had an equalizer as he shot from the edge of the area but saw his effort go just wide.
Sydney enjoyed two free-kicks on the hour mark which allowed Del Piero two opportunities to find team mates but on each occasion the Mariners were let off.
In the 63rd minute the Mariners should have equalized after the ball was not cleared by Vedran Janjentovic who came off his line leaving Trent Sainsbury with an open goal but his header looped over the bar.
Del Piero could have wrapped things up in the 69th minute after John Hutchinson gave away a free-kick but Mat Ryan produced for the Mariners with a superb save to keep the visitors in the game.
Sydney FC's resurgence sealed the match in the 73rd minute as substitute Joel Chianese was played through by Terry Antonis, allowing him to slide the ball under Ryan for a 2-0 lead.
The Mariners tried to find a goal late on but like their whole match it was futile as they couldn't take advantage of the opportunities that presented themselves handing Sydney a win.
The loss all but hands the Western Sydney Wanderers the premiers plate with just three games remaining in the season while Sydney now look a good bet to make the finals.