Level after 24 minutes, the teams continued to give up possession too easily, with the home team the first to cash in when play again broke down in midfield.
Dani Sanchez linked with Daniel, then gathered the return and ran into the Sydney penalty area where he deftly chipped over the advancing Liam Reddy for 2-1 in the 34th minute.
The visitors enjoyed much of the play early in the second half, and from one Phoenix attack they broke quickly from deep, caught the Phoenix defence square, and celebrated as Emerton picked out Brazilian Bruno Cazarine, who squeezed the ball under Tony Warner.
After doing nothing with the first seven corners they won, the Phoenix cashed in on their eighth when Ben Sigmund capped another solid game with a crashing header to regain the lead.
If Sigmund won plenty of kudos for his strike, there was just as much jubilation four minutes into stoppage time when Paul Ifill, on for the last 30 or so minutes, completed the job with a typically well-taken goal.
The visitors had their moments, but for a team boasting talented players like Emerton, Cazarine, Terry McFlynn, Dimitri Petratos, and Mark Bridge, it was a disappointing result.
Herbert would have been heartened by his team's strong first half, even if they failed to convert more of their chances.
The feared Sydney midfield was more than matched by Lia, Tim Brown and Sanchez who also profited from strong overlapping games from fullbacks Manny Muscat and Tony Lochhead. The duo stretched Sydney repeatedly to create chances for Daniel, Sanchez and Chris Greenacre.
That pressure must have had Lavicka fearing the worst as his team conceded four goals for the second time in a week to leave their goal difference at an unhealthy minus four.
It was the result Herbert wanted with five home games left this season. To reinforce their playoff hopes, they must do it again on Sunday when they host Perth, whom they beat at the same ground less than a month ago.
