WHERE Collingwood and Carlton established the "ultimate rivalry" in the old inner Melbourne suburban battles of the VFL, the Port Adelaide and Adelaide football clubs have redefined the battle of superiority in the AFL.

"It is," says Australian Football Hall of Fame legend Malcolm Blight, "and there is no doubt in the AFL - the AFL - that the Showdown is the best rivalry of any of the teams."

Why is this Showdown rivalry greater than other in the AFL - and finding new impetus at a time when Port Adelaide and Adelaide are at stark extremes in their positions in the league premiership race?

"Maybe," answers Blight, "it is the history of Port Adelaide trying to jump in the AFL (in 1990).

"Maybe it is just the fact that us South Australians are slightly conservative when compared to the other States. What you want to do is lead the way. And when you want to both lead the way, there is a rivalry between the clubs to be that leader for South Australia.

"I dead set know Port Adelaide want to. I know Adelaide do. So you have this rivalry whereas in Western Australia, West Coast has always led the way and dominated the derby count against Fremantle.

"Because of the way this (Showdown rivalry) started, in 1990 and with Port Adelaide's win in 1997, and the way the first six Showdowns went with a win for Port Adelaide followed by a win for Adelaide, the mentality of South Australians flowed into a football contest. The Showdown has become part of our psyche."

Blight grew up in Adelaide's western suburbs barracking for Port Adelaide and idolising the goalkicking feats of Port Adelaide premiership hero Rex Johns. After a stellar VFL career as a player with North Melbourne and an era-defining stint as senior coach at Geelong, Blight returned home to be Adelaide's coach in the first Showdown in April 1997.

Blight was staggered by the tension that existed across the boulevard between Alberton and West Lakes even before Crows defender Rod Jameson tried to land a punch on Port Adelaide full forward Scott Cummings at the southern end at Football Park.

"I had a healthy respect for everything Port Adelaide had ever done in the game," Blight said. "I just treated them (Port Adelaide) like Carlton or Collingwood or Essendon or West Coast. They were another team that we had to beat ...

"It was never (for me) the vindictiveness or the hatred that I saw come out in some people in both camps. It was an amazing event ...

"I could not believe the noise in Adelaide in the week of the first Showdown. It was like a grand final week. In some ways, more. Everyone liked one team or the other. Even in grand final week you will find people who barrack for other clubs. But the Showdown split Adelaide down the middle. It was amazing. And the pressure and the build up consumed every single minute of the day. Everyone was talking about this first Showdown. It was remarkable."

Showdown 49 on Saturday night at Adelaide Oval marks the opportunity for a new leader in the derby race that is locked at 24-24. And the current generation of players - many of whom were neither born when the first Showdown was played at Football Park in 1997 nor understand the events of 1990 that shaped today's AFL - are carrying the same blood-stirring feelings of their predecessors by building the rivalry on deep-seated emotions.

Injured Port Adelaide midfielder Zak Butters is 20, born in Victoria and totally ingrained with the spirit of the Showdown rivalry.

"I have a couple of friends who play for Adelaide," says Butters referring to his fellow Victorian junior squad team-mate Lachie Scholl as one friend at West Lakes, "but I wouldn't say I like them."

Port Adelaide president David Koch echoes Blight's read of the Showdown and understands Butters' intense attitude on the derby.

"It is the greatest rivalry in footy," says Koch. "It is my favourite footy week of the year. Why? I love what I call the mixed marriages (between Port Adelaide and Crows fans) and families celebrating the game where partners barrack for opposite teams; where kids will break away from a family tradition and switch sides.

"The passion, the banter, the tension ... it is such great fun.

"We celebrate that we have two wonderful clubs representing South Australia in the AFL."

For the second time in Showdown history, the Adelaide bench will have a senior coach who cut his teeth at Alberton - Matthew Nicks, who follows the late Phil Walsh across the great divide.

Nicks has seen how the Showdown rivalry has been built by both clubs having a deep-seated hatred in missing out on bragging rights at home.

"Showdowns are anything for anyone; I don't know what it is," Nicks said. "It's crosstown rivalry, it's ... I'd like to say mutual respect ... careful with that though.

"The clubs hate each other. And we love that.

"That is what sport is about. There are rivalries across every sport across the world. We have one of the best with the Showdown."

It is the greatest rivalry of all in the AFL.