The hosts are fresh from winning the Elimination final while the visitors are playing their first match for this stage of the competition.
Match preview
There was only two points to separate these two teams in the league table, but Adelaide United had to go through the Elimination Final in order to be here while their opponents got a free pass for finishing second.
The hosts comfortably defeated Wellington Phoenix 2-0 courtesy of a brace from Craig Goodwin, and the experience of knockout football is something that could serve them well heading into this match.
Adelaide United have typically been stronger at home throughout this campaign, and taking a lead into the away leg could end up being crucial.
However, when the two teams met at the Hindmarsh Stadium in the league it was Central Coast Mariners who left with all three points following a dominant performance.
Nick Montgomery's men won that match 4-1 and secured themselves passage to this round of the competition in doing so because it was the final game of the main season.
Adelaide United's goal was nothing more than a consolation in that game which finished 4-1, and considering that was the last time that Central Coast Mariners played, they will be confident of repeating that feat.
The visitors had an impressive campaign overall, finishing in second place which is something that they earned by putting together a five-match unbeaten run.
Montgomery's men were consistent during the business end of the season and they reaped the rewards being able to rest for this match, but whether or not that break will be beneficial remains to be seen.
Central Coast Mariners did not have the strongest form away from home during the main season though which is something they will be wary of heading into this one.
However, they have dominated both games against Adelaide United as their home match saw them win 4-0, therefore they have scored eight against them while only conceding one which will provide plenty of belief.
Adelaide United Australian A-League form:
W
D
L
D
L
W
Central Coast Mariners Australian A-League form:
L
W
W
D
W
W
Team News
Adelaide United are dealing with several injury problems heading into this match with Harry Van Der Saag dealing with a knee problem with Josh Cavallo remaining out due to his Achilles.
Alongside them, Juande is sidelined with a leg issue and Jonny Yull will miss out because of a back injury which is stretching Carl Veart's squad for such a big match.
However, they will be boosted by the return of Zac Clough who has been an important of the team this season, while Alexandar Popovic has also been brought back into the matchday squad.
The visitors have also been able to welcome Yaren Sozer back to the squad ahead of this one after overcoming an injury during the break, but that has led to Anthony Pavlesic making way.
Adelaide United possible starting lineup:
Gauci; Lopez, Barr, Warland, Kitto; Isaias, D'Arrigo; Halloran, Clough, Goodwin; Ibusuki
Central Coast Mariners possible starting lineup:
Vukovic; Roux, Triantis, Kaltak, McGarry; Nkololo, Balard, Nisbet, Silvera; Cummings, Tulio
We say: Adelaide United 1-1 Central Coast Mariners
With this being the first leg of the semi-final it is likely to be quite a nervous and cautious encounter with neither team wanting to give too much away heading into the second game.
Considering that, it would not be a surprise to see the two teams play out a draw in this match, leaving it all to play for in the reverse fixture.