WE have been here before. For the fourth time since Port Adelaide's entry to the national league in 1997, an AFL home-and-away season closes with a critical - top-eight shaping - contest against the league's other portside club, Fremantle.

It first happened in 2005, to take Port Adelaide from ninth to eighth - while Fremantle tumbled out of the finals (seventh to 10th) on the result of the home-and-away season finale at Football Park. A West Australian-born draftee - and future Port Adelaide captain - Dom Cassisi was a key player in the 11-goal second-half surge that sunk the Dockers and allowed Port Adelaide's premiership defence to continue to September.

Then in 2007 it was - as this weekend - the test for Port Adelaide to hold second spot and the rights to a home qualifying final, remarkably against the other West Australian club, third-ranked West Coast.

In 2019, the week began with Port Adelaide needing to beat Fremantle ... and there also was the demand that the eighth-ranked Western Bulldogs fall to South Australia's other AFL team. That result - or favour from the neighbours at West Lakes - did not unfold in the 24 hours before Port Adelaide's home clash with Fremantle at Adelaide Oval. The battle of the port clubs ultimately was a dead rubber.

And now history repeats ... 2007 style when a home-and-away season closer against Fremantle was to the key to a home qualifying final at West Lakes and passage to Port Adelaide's second AFL grand final appearance.

The "final equation" - the most-likely scenario for this weekend's finale to the home-and-away season - is:

PORT ADELAIDE stays second by beating Fremantle in Perth on Sunday, either with a percentage advantage on Greater Western Sydney (currently 114.2 to 111.7) or by points (64 to 60) should the Western Bulldogs defy GWS hours earlier at Ballarat.

PORT ADELAIDE could drop to third - and concede home-field advantage to Greater Western Sydney during the qualifying finals - by losing to Fremantle should GWS account for the Western Bulldogs.

PORT ADELAIDE also could stay second by percentage with defeat to Fremantle ... and find Geelong as its opponent at Adelaide Oval for a qualifying final, should Greater Western Sydney stumble and Geelong thrash West Coast for a percentage booster at Kardinia Park on Saturday afternoon.

PORT ADELAIDE falls to fourth - and enters an away qualifying final with minor premier Sydney - with a heavy defeat to Fremantle and results that give Greater Western Sydney and Geelong critical percentage boosts.

For all these permutations, the key note for the weekend is Port Adelaide holds destiny in its hands. And, by playing last during the round, Port Adelaide will know exactly what is required at Perth Stadium against Fremantle to book a home qualifying final after the pre-finals bye.

For the first time, the Port Adelaide-Fremantle decider of finals destiny is in Perth rather than at Adelaide Oval or Football Park.

The previous three are part of nine memorable finishes to the home-and-away season in Port Adelaide's AFL story, starting with that big finish against minor premier St Kilda at Football Park in the inaugural season of 1997.

THE FREO FINISHES

ROUND 22, 2007: In the penultimate round of the home-and-away season, Port Adelaide completed "mission impossible" by ending Geelong's 15-game winning streak at Kardinia Park. The prize - second spot, but only with a marginal hold on the rights to a home qualifying final: a 0.4 edge on West Coast by percentage (112.5 to 112.1).

The fixture for the 2007 home-and-away season closer stands as a carbon copy of this weekend's agenda. 

West Coast went first on a Saturday afternoon in Perth - and beat 12th-ranked Essendon by eight points (after leading by 44 points at the last change) at Subiaco Oval to command second spot on the live ladder.

Port Adelaide entered Football Park knowing the equation to regain second spot - and home rights for the qualifying finals. A 47-point lead midway through the second term was wrecked by Fremantle - on the back of a six-goal surge during the third quarter - starting the last term with a four-point deficit.

Senior coach Mark Williams took the huddle at the last break to the outer for a wake-up call in front of the Port Adelaide fans.

"We would do that when we needed something special. The players had put the cue in the rack," recalled Williams, "and decided to play in a bit of a protective mode. And then we saw their best under pressure."

Port Adelaide won by 32 points, kept second spot with a 1.8 advantage on percentage - and opened the final series with an epic three-point win against West Coast on a Friday night.

ROUND 22, 2005: Entering the last weekend of home-and-away season, the premiership table was almost a replica of today's ladder. Geelong, Fremantle and Melbourne had positions six to eight with 11 wins; Port Adelaide was ninth with 10 wins and a draw.

Port Adelaide was in the eight (and provisionally sitting in sixth spot) by the Saturday night of round 22 after turning a five-point deficit at half-time at Football Park into a 45-point win with an 11-goal second half while Dom Cassisi and Josh Mahoney each finished the game with four goals.

The win ensured Port Adelaide did not join the list of AFL premiers ordering mothballs before September.

Geelong (by one point on Richmond) and Melbourne (by 10 on Essendon) survived tough closers to push Port Adelaide to eighth spot - and an away elimination final won against North Melbourne by 87 points at the Docklands.

ROUND 22, 2019: As in 2005, Port Adelaide was out of the top eight (ranked 11th) but still in contention for a finals berth on the Monday leading to the home-and-away season closer against Fremantle at Adelaide Oval.

But - unlike this weekend - destiny was not in Port Adelaide's hands.

By Saturday night, Port Adelaide knew it would need a percentage-boosting win against Fremantle to leapfrog the other contender outside the top eight, ninth-ranked Hawthorn.

By Sunday afternoon, it was all irrelevant once the Western Bulldogs locked their berth to the finals with a never-in-doubt 34-point win at Ballarat against the neighbours from West Lakes.

Port Adelaide played for pride in beating Fremantle by 43 points in the last game of the home-and-away series, finishing the season with an 11-11 win-loss record.

THE FIRST

PORT ADELAIDE was tipped to be ranked last during its inaugural AFL season in 1997. Some pundits said Port Adelaide would not win a game. It was placed third with an 8-5 record by round 13 - and went to the last game of the home-and-away series playing for a spot in the top eight.

The match against league-leading St Kilda was rescheduled to 5.10pm on Sunday, August 31 to allow the finals-shaping match to stand alone with a national television audience.

The day began with the world in shock amid news of the death of Princess Diana in Paris - and the mood on the terraces at Football Park reflected that dismay.

On Friday night, West Coast left the door ajar for Port Adelaide by beating eighth-ranked Brisbane by 39 points at the WACA in Perth.

Port Adelaide was in the eight on the live ladder at half-time when it led St Kilda by one point (7.8 to 8.1). St Kilda's six-goal last term - that sealed a 33-point win - ended the dream ...

THE BEST 

OF all the home-and-away battles between Port Adelaide and Brisbane during the epic four-year battle for supremacy between 2001-2004, no game stands with greater class than the home-and-away season closer at Football Park in 2002.

The late Clinton Grybas closed the match commentary declaring this was "the greatest game that was not a grand final".

Port Adelaide was second, behind Brisbane by percentage - 139 to 133.6.

In the traditional Saturday afternoon timeslot, Port Adelaide claimed its first AFL minor premiership with the six-point win with midfielder Roger James scoring the winning goal.

Chad Cornes' duel with Brisbane centre half-forward Jonathan Brown was the centrepiece of this classic match.

The context of claiming that minor premiership in 2002 is more significant than today when the top-two teams have the same benefits - home qualifying finals leading to (by victory) home preliminary finals. In 2002, Port Adelaide and Brisbane also were playing for the guarantee of a home preliminary final while the AFL was contractually committed to the MCG Trust to deliver at least one of the two preliminary finals to the MCG - a deal ultimately rewritten to protect the integrity of the national competition.

Sadly, Port Adelaide forfeited this hard-earned right secured in round 22 - finding itself in a preliminary final at the Gabba against Brisbane by losing the home qualifying final to Collingwood at Football Park. 

THE GAME CHANGER

FROM the dark chapter of 2010-2012, the home-and-away season closer of Season 2011 revealed the new light for Port Adelaide - and South Australian football.

The closer against Melbourne was moved to Adelaide Oval - the first AFL game at the city ground and the public's chance to declare how much it wanted elite football back at its cradle at a redeveloped Adelaide Oval.

The Port Adelaide fans could not have been more emphatic in their response.

"We were told hell would freeze over before we played at Adelaide Oval," recalls then Port Adelaide Football Club president Brett Duncanson.

"I deliberately walked the line outside the oval that day knowing if we had 10,000 at the game we would get smacked," Duncanson said. On that sunny Sunday afternoon in late August, there was a full house of 29,340

"The overwhelming reaction from the fans was, ‘Make sure we come here’. They told me Adelaide Oval felt like home, something Football Park was not for them."

Port Adelaide beat Melbourne by eight points - handing the wooden spoon to Gold Coast - and the game was changed for the better in Adelaide.