Bernie Ibini's sixth A-league goal of the season was enough to send the Mariners to the semi-finals, where they will face Western Sydney Wanderers for the third time in as many post-season campaigns.
Mariners boss Phil Moss made four changes to the side that suffered a 1-0 loss against FC Seoul in the AFC Champions League midweek as defender Eddy Bosnar returned, Glen Trifiro was brought into the starting line-up with Nick Fitzgerald and Ibini named in attack.
Both sides opened with purpose but Adelaide had the best early chances, with a lack of cutting edge letting them down on several occasions.
Seven minutes before the interval applause rang out throughout Central Coast Stadium in tribute to Dylan Tombides after the West Ham and Australia Under-23 striker lost his battle with testicular cancer on Friday.
The Mariners started the second half the stronger side with Ibini and Mitchell Duke combining as the former saw a low effort saved by Eugene Galekovic.
Adelaide made the game’s first change with 30 minute remaining as Bruce Djite replaced Jeronimo Neumann, but it was the Mariners who scored the breakthrough goal soon after, with Ibini thrashing the ball past Galekovic after an expert lay-off from Duke.
The game ended on a sour note as substitutes John Hutchinson and Awer Mabil were booked for their part in a brawl, but Central Coast were soon celebrating as they secured a final-four spot for a fourth straight season.
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