The A-League leaders produced a dominant display to brush aside the fourth-placed Mariners with relative ease to clinch a new competition record for going 14 matches without a loss, surpassing the previous record of 13 held by Adelaide United.
Two early goals from in-form Costa Rican striker Jean Carlos Solorzano set up the win with Mitch Nichols and Reinaldo, plus an Alex Wilkinson own goal, finishing off the damage and it was a performance adulated by the coach.
"It's not easy in this league to go undefeated at any stage, but in particular over such a short period of time and with so much travel thrown in," Postecoglou said.
"The players have done unbelievably well to cope with everything that's been thrown at them during the run.
"What we need to do now is to keep going and keep improving on the things we can.
"It was a fantastic performance from the players today," he added.
"Right from the first whistle you could tell they were up for the match and you could see we learned our lessons from the midweek game.
"The passing was a lot sharper and we were even more clinical than we have been in front of goal."