A win would have seen Sydney move equal with Melbourne Victory, who play Newcastle Jets Sunday, on 33 points and with just six minutes of normal time remaining they were in cruise control.
Leading 2-0 thanks to goals from George Blackwood and Shane Smeltz, Sydney coach Graham Arnold would have been confident in taking home the three points, but late goals from Roy O'Donovan and Harry Ashcroft tied the match up meaning Sydney is without an A-League win in 64 days.
Sydney FC coach Graham Arnold blamed sloppiness and mistakes for the result after his side dominated throughout the majority of the match against a largely disjointed and ineffective Mariners.
"It's our fault," Arnold said. "At 2-0, it should have been three, four, five ... (but we) kept them in the game."
"It was sloppiness and individual mistakes that cost us the win."
Although he made six changes to the side that started an AFC Champions League game in Korea midweek, Arnold said he expected the players who were backing up to show fatigue in the final stages of Saturday's game.
An animated Arnold clearly showed his anger on the sidelines after the Mariners' equaliser.
"When you threw away points like that, you kill yourself," Arnold said. "It's got nothing to do with tactics, game plans ... just concentration."
Mariners coach Tony Walmsley praised his players' belief and character.
"The questions I had at halftime were around the run we've been on. Have we got the belief to keep going?" Walmsley said.
"I was really pleased for the fans that were here. They made a great noise and brought us home, and for the players who have never given up.
"The mood in the camp is incredibly positive. They don't train like a team at the bottom of the league and today showed there's always something to play for, so I'm very proud of them."
George Blackwood opened the scoring in the 10th minute with a brilliant solo effort, collecting the ball from Mickael Tavares on the half-way line, he ran virtually unopposed until the edge of the box where he launched a curling right-foot shot into the far corner.
The Mariners could argue they should have had an equaliser in the 42nd minute when Roy O'Donovan put the ball in the net only for it to - incorrectly as replays would show - be ruled out for offside.
Sydney FC showed no mercy just three minutes later when a quick Brandon O'Neill free-kick found Shane Smeltz in open space. The New Zealand international easily cut inside before placing his shot beyond Paul Izzo to record his 89th A-League goal, putting him one behind all-time leader Archie Thompson.
It could, and probably should, have been 3-0 in the 49th minute when Smeltz had an almost empty net to aim at, however his shot was blocked on the goal-line by a diving Harry Ashcroft.
Sydney had numerous chances to add to their 2-0 lead in the second half but failed to do so, allowing the Mariners hope of a result.
In the 86th minute Brandon O'Neill, who for the most part had performed well throughout, coughed up the ball in midfield. The Mariners pounced and Matthew Fletcher delivered a perfect cross that was volleyed home by Roy O'Donovan to give Central Coast their first goal in three matches.
That goal sparked the Mariners into life as they pushed for the equaliser and it duly arrived a minute into time added on when Vedran Janjetovic allowed a long distance drive from Ashcroft to slip through his fingers and into the net.
Sydney FC could now be six points outside the top six by the end of the weekend, while the Mariners snap a six game losing streak that will give some hope to their fans.
