Meanwhile, the home side have been left to play for pride after recording six successive defeats, moving the club down to 10th position in the standings.
Whatever happens during Macarthur closing double-header, supporters can take several positives from what has been a productive first-ever campaign in the A-League.
However, there would naturally be disappointment if they miss out on the top six, something which is a possibility after failing to win either of their last two fixtures.
The bigger pressure remains on the chasing pack, but Macarthur could find themselves in the bottom half of the table if they fail to overcome their faltering next opponents.
The Bulls had been on their way to overtaking Central Coast Mariners on Thursday before the visitors battled back to claim an important 2-1 victory.
Ante Milicic now hopes that his players can extend their unbeaten away record to four matches after recently benefitting from three other trips to lower-table opposition.
As far as opponents Western United are concerned, they are desperate for the season to end after their capitulation since the beginning of May.
Twenty goals have been conceded during six successive defeats, a remarkable collapse given that they had previously collected 14 points from seven games.
Having suffered a 6-1 defeat at home to 11th-placed Melbourne Victory, Mark Rudan was not shy in criticising his under-performing squad.
Whether that was the right move remains to be seen, but Rudan needs to get a reaction out of his players if he is save his own job in the dugout.
Rudan will inevitably ring the changes after Western United conceded four first-half goals against Victory.
Tommy Oar is also an option in a creative position after making his comeback from injury against the Mariners.
Western United possible starting lineup:
Scott; Pierias, Imai, Durante, Calver, Pain; Diamanti, Skotadis, Lustica, Guarrotxena; Wales
Macarthur possible starting lineup:
Federici; McGing, Milligan, Susnjar, Meredith; Martis, Genreau; La.Rose, Susaeta, Najjar; Derbyshire
We say: Western United 1-2 Macarthur
Despite their disastrous recent form, Western United will feel that they have an opportunity to get back on track on Monday. However, we think that Macarthur will still be able to edge out their hosts, potentially by the odd goal in three after a fast start to proceedings.