The Mariners beat Melbourne Victory 2-0 in a pulsating game at Bluetongue Stadium - one of five matches played back-to-back across Australia and New Zealand on Wednesday in the A-League's first marathon.
But second-placed Melbourne Heart faltered to give the Mariners some breathing space at the top - the Heart losing 3-1 to resurgent Adelaide United at Melbourne's AAMI Park.
Central Coast striker Matt Simon scored twice on his farewell to plunge the Victory to their third successive defeat.
Simon, who has signed with Korean side Chunnam Dragons, was inspirational as the Mariners stretched their unbeaten run to 11 games.
He scored inside 19 seconds, and again with five minutes left to seal a win in an end-to-end clash of the highest quality in front of more than 12,000 fans.
Adelaide United's resurgence under John Kosmina continued - the Reds unbeaten in his three matches in charge and emerging as live finals chances.
After being battered in the opening 20 minutes, the Reds went on to control the match against the competition's form team in front of a bigger than usual Heart crowd of more than 8,000.
Sergio van Dijk scored twice, with Dario Vidosic netting once to snap the Heart's five-match winning streak.
Heart coach John van 't Schip said his side's defeat to a side struggling badly just three weeks ago showed the evenness of the competition.
"We had a good run and in those games we played some good football, but there were also some moments where we didn't play that well and we scored," van 't Schip said.
"It's a very competitive league. We want to go as high as possible. Our goal was getting into the playoffs, and it's still our goal.
"But we want to finish as high as possible." Wellington punished Sydney FC's leaky defence with a 4-2 win at Westpac Stadium.
The Sky Blues have now shipped eight goals in their past two matches - the Phoenix scoring twice in the last 15 minutes to break a 2-2 deadlock.
Newcastle survived a huge Gold Coast United fightback to run out 3-2 winners in their clash at Ausgrid Stadium.
The Jets led 2-0 with 20 minutes remaining and were cruising, before United hit back with two goals in six minutes to level the scores.
But striker Labinot Haliti scored Newcastle's winner from the resulting kick-off after Gold Coast's second goal.
Brisbane Roar and Perth Glory finished off the day's action with a topsy-turvy 3-3 draw at nib Stadium.
Brisbane fought back after trailing 2-0 for most of the first half, but coach Ange Postecoglou thought his side was "rubbish".
"Perth Glory got robbed to be honest," a forthright Postecoglou said.
"They deserved to win the game today. We were very ordinary and it would have been an injustice if we got anything more than a point out of it."