A free Commins Menapi headed the visitors into the lead - a situation they perhaps deserved in a first half in which they were the more settled and controlled side.
Just after half time, a Shane Webb through ball to Awaritefe was totally missed by the later - but embarrasingly also by the advancing Cosmos keeper Konstantinou. Even the ball seemed to go red with shame as it ambled into the empty net.
2-0 was stretching United's performance beyond its modest level - and the Cosmos began to take over, as if indgnant at the injustice of it all. Robby Hooker was always involved in an unaccustomed midfield roll in which he often misdirected the ball - resulting in pressure from what must be the NSL's only all black strikeforce.
Once again it was the entry of the tiny Uruguayan Milton Cortes (in the 60 min) that sparked the home side. Arranz down the right and Lyons on the left, stretched the Utd rearguard and it seemed only a matter of time before the close skills of eithe Cortes or Castro would take advantage.
In fact both of them featured in the 70min goal when Castro was played through on the left side of the penalty area and his chip was headed on and into the net past a diving Hughes, by Cortes - who must played for Lilliput in the Uruguayan 1st Div, such is his size - but not his stature amongst Cosmos fans.
The rest of the half was dominated by the home side, featuring moments of high farce, such as when Konstantinou wandered 35m out of his goal, tried to dribble around a couple of Utd players, lost the ball, and was grateful there were more stable teamates than he to clear the danger.
The Cosmos looked to have equalised in the last minute as a Castro header flashed past Hughes, but captain Aytec Genc was just tall enough to head it off the line and over the bar.
A game Cosmos did not deserve to lose, though little should be said of their limited travels in the first half - swift they were not - and in the end, beaten they were, for the first time at home under Milovanovic.