Sydney FC's hopes of sending coach Vitezslav Lavicka out a winner have taken a severe battering after three former Sky Blues stuck the knife in as Newcastle ran away 5-2 winners at the SFS.
Nikolai Topor-Stanley scored the Jets' opening goal after 22 minutes and Ruben Zadkovich rubbed further salt into Sydney's wound with a wonderful strike seven minutes later.
Kiwi international Jeremy Brockie added a third on 38 minutes and by that stage Lavicka must have wished he was on the first plane back to Prague.
But second half goals to Hirofumi Moriyasu and Michael Beauchamp - the defender's first senior goal in an Australian league - threatened to turn the game on its ear before Brockie put the result to bed with his second in the 87th minute.
Ali Abbas completed the rout with an injury time goal - the first time Sydney have conceded five goals at home.
The Sky Blues could have gone five points clear in sixth place but instead have been dumped to seventh, with the Jets taking their spot inside the top six.
They have now been dragged into a dogfight that threatens to ruin plans to farewell the popular Lavicka with a finals appearance.
Adding to the pain, it was three players who once called the SFS home that did the damage.
Topor-Stanley, Zadkovich and Brockie all spent time at Sydney and delighted in putting their old club to the sword.
Liam Reddy did well to block Ryan Griffiths' attempt at goal but the rebound fell for Topor-Stanley, who expertly looped his header just inside the far post for the first of the afternoon's seven goals.
If that stunned the Sydney faithful they were sent further into shock when another old boy doubled the advantage in the 29th minute.
Tarek Elrich headed a pass into Zadkovich's path and the shaven-headed No.10 let fly with a first time half-volley that screamed past Reddy and into the right-hand corner of the net.
Zadkovich provoked the Sydney fans by celebrating at their end, turning his back and pointing to the name on his back as the abuse rained down on him.
Sky Blue fans had more to worry about when a diving Brockie headed home a beautiful cross from Elrich to fire the Jets ahead 3-0 just before the break.
The home side was booed off at half-time and were stung into action as a result.
Moriyasu pulled a goal back just two minutes in, cutting back on his right foot and slamming a hard, low drive past Ben Kennedy's outstretched left hand.
Beauchamp had never scored a goal in more than 100 league appearances in Australia but broke his duck in the 72nd minute to really set the game alight.
But despite pouring on the pressure the hosts could not buy a third goal.
Brockie's second three minutes from time sealed Sydney's fate before Abbas added to the embarrassment.
Sydney FC 2 (Moriyasu 47m, Beauchamp 72m)
Newcastle 5 (Topor Stanley 22m, Zadkovich 29m, Brockie 38m, 87m, Abbas 95m)
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