The Roar had gone 36 games unbeaten - an Australian record across all football codes - until Sydney FC recorded a 2-0 victory at the WIN Jubilee Stadium in Kogarah on Sunday to knock them off their perch.
Dimitri Petratos grabbed an early goal for the home side before Brett Emerton doubled the lead in the 19th minute which was enough to see the Sky Blues jump to third and send a title challenge warning to the Ange Postecoglou's men.
Earlier in the round of matches, Central Coast Mariners controlled proceedings at Hindmarsh Stadium to defeat Adelaide United 4-0 on Friday night with goals coming from Mustafa Amini, Bernie Ibini-Isei, Patrick Zwaanswjk and Rostyn Griffiths to retain second spot as the Reds fell to ninth after a third winless outing.
Perth Glory returned to the winners list following four losses from five games with a 2-0 home win over rock-bottom Gold Coast United courtesy of penalties from Mile Sterjovski and Shane Smeltz, whilst Melbourne Heart grabbed a 1-0 home win over Morwell thanks to Mate Dugandzic's 41st minute goal to defeat Wellington Phoenix.
And the Newcastle Jets' solid home form continued with a 3-1 win over Melbourne Victory putting them in fourth position as the losers fell back to seventh. A double from Ryan Griffiths either side of Labinot Haliti's early second-half strike was enough to overcome Carlos Hernandez' fourth goal in three appearances.
2011/12 A-League season scores - Week 9
Melbourne Heart: 1 (Mate Dugandzic 41') Wellington Phoenix: 0 La Trobe City Stadium, Morwell