Only a draw would be enough for their objective but Sydney, despite languishing in seventh place, can make the cut too with a victory.
The Wanderers arrested their three-game losing run with a 2-0 defeat of Brisbane Roar last week. Bernie Ibini-Isei and Bruce Kamau scored to secure all three points and keep their knockout hopes alive.
Adelaide could have long secured their place in the next round had it not been for their erratic run lately. They were left battered 4-1 at the hands of Sydney in their last outing.
Jordan Elsey was sent off in the match, Adelaide's third red card in seven games, as discipline has become a huge problem for Carl Veart's side.
Adelaide United vs Western Sydney Wanderers Head-To-Head
There have been 27 games between the sides, with Adelaide United narrowly edging Western Sydney Wanderers with 10 victories to eight.
In their first-leg clash this season, the sides played out a 1-1 stalemate in Adelaide.
Adelaide United Form Guide (all competitions): L-W-L-W-L
Western Sydney Wanderers Form Guide (all competitions): W-L-L-L-W
Adelaide United vs Western Sydney Wanderers Team News
Manager Carl Veart has no injury concerns to deal with. However, he'll be forced to make at least one change, as Jordan Elsey was sent off in the last match and will be suspended.
Suspended: Jordan Elsey
Western Sydney Wanderers
The Wanderers are likely to play the same lineup that beat Brisbane Roar in the last match. However, Tate Russell could force a solitary change by replacing Daniel Wilmering.
Adelaide United vs Western Sydney Wanderers Predicted XI
Adelaide United (4-2-3-1): James Delianov; Ryan Strain, George Timotheou, Michael Jakobsen, Ryan Kitto; Javi Lopez, Joshua Cavallo; Ben Halloran, Stefan Mauk, Craig Goodwin; Alhassan Toure.
Western Sydney Wanderers (5-3-2): Daniel Margush; Thomas Aquilina, Ziggy Gordon, Dylan McGowan, Tass Mourdoukoutas, Tate Russell; Steven Ugarkovic, Graham Dorrans, Keanu Baccus; Bernie Ibini-Isei, Bruce Kamau.
Adelaide United vs Western Sydney Wanderers Prediction
Both sides have something at stake here and hence it's difficult to see a winner.
However, the home side only need a point to secure their place in the knockout stages and have enough quality to achieve that.
Prediction: Adelaide United 1-1 Western Sydney Wanderers
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