First half substitute Brendan Gan headed the Sky Blues' opening goal in the 77th minute before marquee player John Aloisi added the second nine minutes from time to seal Sydney's third win of the season.
"I appreciated all the players' passion and activity," said Sydney coach Vitezlav Lavicka after the match. "I have to say it was a similar game against Adelaide (United).
"We are happy, but I have to repeat, round 4 is gone - nothing more, nothing less."
Opening goalscorer Brendan Gan said he was happy that all the set-piece practice at training sessions had paid off after he headed home in the 77th minute.
"We practiced that (corners) at training. I should have put the first two away but the third is all that counts," Gan said of the goal. "The game goes for 90 minutes so we're all going to go for that whole 90 minutes and it paid off in the end."
A swift counter attack late in the game saw the Sky Blues surge forward in numbers. Brosque took the space on the left flank and produced a tantalising cross which was finished unerringly by Aloisi to confirm the win and the three points for Sydney FC.
The victory sees Sydney hold the outright lead in the Hyundai A-League for the first time since Round-12 in Season One of the Hyundai A-League. Next up for Vitezslav Lavicka's undefeated men is a top-of-the-table clash with second-placed Gold Coast United at Skilled Park (Gold Coast) next Saturday night.