Sydney FC remain top of the A-League table after defeating Central Coast 1-0 at Netstrata Jubilee Stadium.
It was the sixth consecutive win for the defending champion Sky Blues and their eighth of the season.
A week after they thrashed Brisbane 5-1, Sydney were in cruise control on Saturday night against the Mariners after the opening goal from Kosta Barbarouses.
It looked as though they were headed for another huge win when their New Zealand international striker scored an effortless goal in the fifth minute.
However, the visitors tightened their defence and created plenty of chances to keep Sydney coach Steve Corica sweating until the final whistle.
"We're not going to win every game 5-1 or 5-0," he said. "Sometimes, a 1-0 victory is even more important. A clean sheet, I'm extremely happy about.
"Sometimes, you have to win those games and put on a good defensive performance.
"We can't play at our best all the time and, when you aren't at your best and you get a result like that, I think it's very important for team spirit."
After the opening fumble, the visitors quickly responded at the opposite end with a Daniel De Silva shot brilliantly saved by keeper Andrew Redmayne.
The crowd of 10,256 was relaxed with the lead until the 89th minute when Mariners midfielder Giancarlo Gallifuoco's header was saved by Redmayne, who was on the spot again.
They went down fighting, but it was not to be for the Mariners, who slumped to their fifth loss of the season.
"We wanted to win today. We didn't come here for a draw - we wanted to win," said coach Alan Stajcic, who was proud of the heart his team showed against the champions.
"I think because the competition is so close and it is so tight that anyone can win any game. It's the closest it's been in a number of years.
"We came here to win tonight. We wouldn't have been happy with a draw either. It's extremely disappointing."
The Mariners are bottom with seven points for the season from two wins and a draw.
Next week, they will face Adelaide United, while the Sky Blues will aim to keep their winning streak alive against Wellington.