The remaining 500 public tickets sold out in three minutes via the Ticketek website when they were released at midday Wednesday.
Public sales for 'walk-up' supporters will not be available at the ticket office on the day.
It means the only way anyone - be they Port Adelaide, Crows or neutral followers - can see the game is by purchasing either an Essential Power membership or 11-game reserved seat season ticket with Port Adelaide.
Essential Power membership provides non-reserved seating access into the Western Stand at Adelaide Oval for all Port Adelaide home games, sharing this stand with the Adelaide Oval football members. Essential Power also provides an AFL Grand Final ticket guarantee (if Port Adelaide is a competing club) and reciprocal rights to the MCG into the AFL Members’ reserve for the 2014 AFL home and away season
There are a few hundred reserved seat memberships still available in either the Eastern or Riverbank Stands, with Club 1870, Black Diamond, Platinum and Gold categories still to choose from.
Port Adelaide’s general manager of member services Matthew Richardson emphasised the need to get in quick to ensure a seat at the Showdown with a season ticket.
"The Essential Power membership is really prime viewing - you can sit anywhere in the Western Stand, you can purchase guest passes for non-Showdowns and you're right near the player benches on the wing.
"It's been a very popular package this year and will continue to be with the club almost sold out of our 11-game reserved seats."
The Port Adelaide membership tally is fast approaching 49,000 members after the club boldly targeted a total membership figure of 50,000 at the beginning of its campaign.
With daily membership sales averaging over 200, Richardson does not expect the rate of uptake to reduce, even after the Showdown.
"It's a magnificent stadium, with great views of the Hill, heritage scoreboard and St Peters Cathedral and the spectacular new Riverbank and Eastern Stands," said Richardson.
"Post-Showdown, the opportunity to purchase a 3-game membership or even the general admission season ticket at only $175 for the remaining 10 games is brilliant value.
"And when people see what our club has planned for gameday - not just for the Showdown, but every game - they'll be truly blown away by the football experience.
"We want to redefine what a day out at the footy is - Port Adelaide is coming to town and you really don't want to miss this."
You can join the club by directly purchasing your Essential Power or 11-game reserved seat via the weareportadelaide.com.au website or by calling the membership hotline on 1300 GO PAFC (1300 467 232).