The Wanderers were on the back foot after an error by goalkeeper Lawrence Thomas opened the door for Felipe Gallegos to draw first blood in the 45th minute at Go Media Stadium on Saturday.
But Milanovic returned serve thanks to a Gabriel Cleur assist in the 51st minute to salvage a point in front of 18,342 fans at the Auckland venue.
Milanovic now leads the league's Golden Boot race with Western United striker Noah Botic, the pair both boasting 11 goals this season.
Black Knights star Guillermo May was left beside himself when he sent their best shot at restoring their lead flying over the crossbar from point-blank range in the 81st minute.
Wanderers substitute Jack Clisby found himself in the same position six minutes later after his close-range shot hit the crossbar.
Western Sydney can finish the round as high as fourth on 36 points after extending their undefeated run to eight matches.
Auckland are still in pole position for a maiden premiership plate, eight points clear with four games remaining.
Gallegos claimed his first ALM goal after punishing Wanderers captain Thomas duly for erroneously gifting him the ball just outside the box.
It was a sucker punch for the visitors, who had hit the scoreboard first in the 29th minute before VAR disallowed the goal for offside.
Bozhidar Kraev had buried the ball for what would've been his fourth goal in four matches thanks to a Brandon Borello assist, but Zac Sapsford was found by VAR to have strayed offside when he heel tapped to Borrello.
Kraev tried his luck in the 21st minute but was denied by former Wellington Phoenix teammate and Auckland goalkeeper Alex Paulsen, before Borrello was stopped in the box by a dogged Dan Hall three minutes later.
Max Mata almost added to Auckland's lead with a bicycle kick deep into the six minutes of added time before the break but Thomas was able to palm off the threat.
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