A second-half Bernie Ibini strike has set up a thrilling Grand Final rematch as the Mariners made it seven straight wins at Central Coast Stadium against the Reds.
The 1-0 win ensures the yellow and navy will travel down the F3 to Sydney's west where they will be hosted by the Wanderers on Saturday night in week two of the finals series.
Adelaide will be dissapointed that they couldn't make the most of a 64-36 percent disparity in the possessions stats, as the Mariners defencive quality shrone through for the second week in a row.
On a night where both teams paid tribute to the late Dylan Tombides - with a minute of silence being observed before kickoff and a minute of applause midway through the match, it was the Mariners who made the most of a cagey clash where their threat on the counter attack proved too much for Adelaide's often fragile back four.
The visitors had the better of the first half with Jeronimo Neumann and Fabio Ferriera posing a threat down either flank. The Mariners were up for the challenge however, just a week after wearing down the attacking flair of Brisbane Roar, and many of Adelaide's opportunities failed to test Liam Reddy between the sticks.
John Hutchinson's introduction for the home side a little after the hour mark seemed to galvanise the side as their attacking raids sharpenend along with their decision making, and it paid dividends on 67 minutes.
Ibini latched on to a diving Mitchell Duke's lay off on the far corner of the box, before a terrific first touch followed by a powerful second shot the ball past a bewildered Eugene Galekovic at his near post to give the Mariners the lead.
The match proved a spiteful one, epitomised by a Cameron Watson tackle on Nick Fitzgerald seconds before the Mariners goal that was barely considered legal in the NRL, as 8 yellow cards were awarded between the two sides. The fixture threatened boiled over just before full time when Adelaide realised a spot in the semis had slipped through their grasp again, but the all in was quickly contained as the Central Coast progressed through to their fourth consecutive semi finals appearance.