Western Sydney claimed their first victory of the season, outplaying Sydney FC 2-0 in what was a heated derby clash at Allianz Stadium.
The Sky Blues, who last week capitulated against Brisbane after Alessandro Del Piero left the pitch with a calf complaint, again appeared rudderless without their injured skipper in suffering their first home loss in nine matches.
The Wanderers' own Italian import Iacopo La Rocca opened the scoring early with Shinji Ono rounding out the goals in front of a record crowd of 40,388 at Allianz Stadium, topping Sydney's previous mark for a regular-season match.
With both teams locked at a win apiece and a draw in three previous derbies, the Wanderers can now claim bragging rights.
Serbian recruit Nikola Petkovic provided the only glimmer of hope for the hosts, with his long-range missile that hit the crossbar 10 minutes before the break their best chance of the match.
It was Sydney's defending from set-pieces that was their undoing in their 6-0 drubbing by the Roar and they were guilty of making the same mistakes.
La Rocca, replacing the injured Aaron Mooy (concussion) in the starting line-up, broke the deadlock in the 11th minute off an Ono corner as the Rome-born journeyman was barely challenged by the Sky Blues' backline.
Youssouf Hersi, who was a constant menace down the right for Sydney, looked to have doubled the advantage moments later but was ruled off-side.
The second goal was again the result of poor defending with Tiago Calvano and Sebastian Ryall unable to dispossess Ono, who off balance managed to slot the ball home for a 2-0 lead in the 26th minute.
Nicky Carle, who wore the Sydney FC captain's armband in place of Del Piero, was also tasked with providing the creative spark in the Italian's place but took until the 84th minute to have his first shot on target.
And while starting the second half strongly with speedy Panamanian Yairo Yau replacing Mitchell Mallia in attack, Sydney just weren't able to match the Wanderers' fire-power.
Earlier, Central Coast Mariners chalked up the first win of their A-League campaign with a 1-0 win over Adelaide United at Bluetongue Stadium.
Nick Fitzgerald's second-minute strike sealed the points against an enterprising Adelaide, who slumped to a ninth successive defeat to the Mariners.
The defending champions had plenty of opportunities to make the scoreline more comprehensive with a dominant second-half display but failed to take their chances in front of a crowd of only 9,109.
Substitute Matt Simon missed a gilt-edged opportunity when he blasted over from close range after Mile Sterjovski's effort came back off the post and on the stroke of halftime Fitzgerald's side-footed attempt hit the bar from less than a metre out with only Eugene Galekovic to beat.
Adelaide, under former Barcelona youth team coach Josep Gombau, have adopted a slow, patient approach revolving around the enterprising Spanish pair of Isaias and Sergio Cirio.
Cirio, playing just behind lone striker Brett McGrath, was an ever-willing runner but for all their possession the visitors had no cutting edge in the final third and Justin Pasfield in the Mariners' goal was largely untroubled.
From the opening whistle the visitors showed their intentions, building from the back, but the Mariners happily sat back and caught them on the break with McGrath lacking the support in attack to worry the home side's well-marshalled defence.
After the break Graham Arnold's side dominated in midfield but failed to add a second goal to kill off the game.
Michael McGlinchey went close with a well struck free-kick that Galekovic tipped behind and the veteran keeper was on hand again to save his side when he raced out of his box to clear from the onrushing Mitchell Duke.
But four minutes from time Adelaide almost made the home side pay for their profligacy when Cirio's magical footwork took him past three Mariners defenders, but he rolled the ball past the wrong side of the post.