PICK your favourite Showdown. There are 54 in the collection, 27 that can be quickly dismissed ... 

Although Showdown XXXIX - the Phil Walsh tribute of July 2015 when Port Adelaide came hard at the end to narrow the margin to three points - might make the list reach 28 for the heart-filled emotions that still linger from that derby.

The Showdown - with a 27-27 win-loss ledger - does after 27 years (on the field that is) live up to all Hall of Fame legend Malcolm Blight means when he declares "no doubt, (this is) the greatest rivalry in football".

The derby justifies all Port Adelaide declared to the AFL through 1992-1994 - during the debate for the second AFL licence based in South Australia - that the city of Adelaide needed two starkly contrasting football clubs.

Where Adelaide is white, Port Adelaide is black; where Adelaide turns left, Port Adelaide swings right ...

For 34 years with verbal jousting and 27 years of on-field battles, the Showdown has captured more than the attention of South Australians. And on Thursday night, for the first time in a home-and-away season, the derby has a stand-alone timeslot (Thursday night) and national free-to-air television coverage.

The expectation is for yet another Showdown that does, as Port Adelaide coach Ken Hinkley notes, deliver the most remarkable and unpredictable script in sport.

"You just know what Showdowns do," Hinkley says. "You think, 'How can they keep delivering and ending up as epic (games and finishes).'

"It is remarkable, weird. There has been a miraculous amount of games ...."

Since the first Showdown at Football Park in April 1997, there have been:

SEVEN derbies decided by a goal or less,

THIRTEEN with a margin between seven points and two goals,

Another ELEVEN settled by 13-24 points.

That is 31 of the 54 derbies with tight or competitive margins.

Describing the essence of the Showdown rivalry in words - even with Blight's strong testimony - has repeatedly fallen into the shadow of what the derby produces on the field.

The game clears away the notion any South Australian (by State parochialism) can barrack for two teams. Showdowns reveal the true heart of every supporter.

The build-up - this week a very short affair - creates apprehension and tension that at times has spilled over while two clubs, their player bases and their fans declare they hate each other.

And let's not get confused on what this "hatred" means. Hinkley summed up the rivalry - a sporting rivalry - just as it is with his remarks last year: "It is a genuine rivalry ... it is a genuine sporting rivalry. There is genuine hatred - and I am not frightened to use the word hatred - because it is a sporting rivalry. It is not a personal thing. Everyone in this State loves the fact both teams want to get each other - and get them good."

After 27 years, all that made the Showdown a must-see event at West Lakes on April 20, 1997 is just as relevant today and driven by either history (SANFL and AFL alike) or a simple workroom bet on a carton of beer decided by the result.

It is the one time hearing Bruce McAvaney say "special" finds its perfect place in the echo of a Showdown commentary. 

Unlike the other non-Victorian derbies in the national competition - the Western Derby in Perth, the Q Clash in Queensland and the Battle for the Bridge in Sydney - the Showdown has repeatedly delivered on and off the field (including in a pub car park when the competing players crossed paths again after the first derby of 2002).

The game's name - Showdown - truly has exceeded all that was envisioned when the marketing executives at SA Brewing (the first derby sponsor) put their badge as a sponsor on the contest in 1997.

It is the one time that four premiership points do mean more than usual. There are the bragging rights, the oft-noted theme from players who say the streets are hell to walk after a derby defeat and the never-fading memories from a football game that to outsiders has become an obsession in South Auatralia.

But which is your favourite?

Is it the first, the game every Port Adelaide fan knew was seven years in the making after the club's AFL ambitions in 1990 delivered no licence but a new rival known as the Adelaide Football Club? The 11-point win marks one of coach John Cahill's greatest achievements.

Is it the last at Football Park in August 2013 when Angus Monfries produced the bouncing goal that turned to the right, drawing comparisons to anything Shane Warne could have conjured on a cricket field? "I haven't seen anything like that; if Pythagoras is watching, explain that," said Dennis Cometti from the television commentary box while the countdown clock hit 87 seconds and the scoreboards showed the deficit was just two points.

It also is worth remembering that Port Adelaide was 20 points down with five minutes to play ... and Chad Wingard's fifth goal made the derby end as a four-point win for Port Adelaide.

"Such was the belief of the group in our ability, game plan, and fitness," recalls Hamish Hartlett, "we never thought we were entirely out of any game. We also had some pretty big comebacks earlier in the year, so that was always in the back of my mind.

"Angus Monfries’ goal late in the last quarter to get us back within a few points. The way the ball bounced at right angles and went through for a goal was something I had never seen before. For it to happen in a Showdown when the game was so tight made it that extra bit more special."

Port Adelaide left Football Park with a  19-16 winning record that can never change. And it went to Adelaide Oval on March 29, 2014 to win the first derby in the city centre by 54 points with Dwayne Russell closing the commentary saying: "Port Adelaide will own this moment in history forever."

Or is the ultimate classic from the heart-pumping finish of Steven Motlop, in his first derby, scoring the winning goal in Showdown XLIV in round eight, 2018 with 21 seconds to play? The derby is also notable for Robbie Gray's six goals, five in the third term.

The Showdown is an extraordinary rivalry, an event that some suggest has become an obsession in South Australia. It defines so much of the city, the state, its people and its football heritage that pre-dates the national AFL but vindicates so much of what Port Adelaide envisioned after the grand storm of 1990.