They've only been butting heads for seven years but after next weekend, Sydney's two AFL clubs will have already played more finals derbies than any of the other more established rivalries outside Victoria.
When the Swans and Giants clash at the SCG on Saturday, it will be their second September battle following their 2016 qualifying final match-up.
Port Adelaide and Adelaide have met only once in finals, West Coast and Fremantle have never done so, and in Queensland, neither Brisbane nor Gold Coast have made it into September since the Suns entered the competition in 2011.
"In terms of the (Sydney) rivalry and where it's got to, I don't think the AFL would have envisaged that this could happen so quickly," former Swans' co-captain Kieren Jack told AAP.
"There's a genuine rivalry there now and rivalries are built off close games and finals games.
"This is our second finals game already in the short space that (GWS) have been in."
Jack is no stranger to September action, having played in 21 finals.
He's better qualified than most to comment on the growth of the Sydney derby, having missed only one of the 15 matches since it started in 2012.
The 31-year-old has re-established himself in the side during the past one-and-a-half years after a hip injury led to a tough start to his 2017 campaign.
With Sydney short on fit players and experience, he battled on through the early rounds but his lack of impact prompted speculation he was nearing the end of his career.
The club later revealed Jack had been playing with injury and rested him for five games.
Those were the only matches he missed that season and he has again been a regular part of the 2018 line-up.
He has missed four games, one when he was rested for a sore hip and three after he suffered a medial ligament injury.
"The knee injury was probably a bit of a blessing because I was able to really freshen up," Jack said.
"Now I feel really good heading into the finals series."
