BEFORE the 27 disposals against West Coast, before the match-winning goal against St Kilda and before establishing himself as a key part of Sydney's preliminary final side, Jai Serong experienced the moment that changed everything: a wet pre-season stint on the wing at Henson Park.

Serong's transition from a standout Box Hill VFL player, where he won back-to-back best and fairest awards between AFL appearances, to a versatile and integral part of Sydney's preliminary final side has been remarkable. 

After struggling for senior opportunities behind Hawthorn's stacked backline, Serong made the switch to Sydney, citing the instant belief shown by senior coach Dean Cox as the key reason behind his move north. 

The decision was not without alternatives. Fremantle was also interested during last year's trade period in a move that might have reunited him with his older brother, Caleb, but Sydney's long-term vision ultimately proved decisive.

The Swans' coaches and recruiters viewed the Victorian as far more than a key defender, believing his running power, versatility, and football intelligence could translate to wing and midfield roles, providing the flexibility that has become increasingly valuable in modern systems.

The 23-year-old quickly proved his value at AFL level, collecting 27 disposals, 10 marks and a goal in Sydney's 128-point win over West Coast in round four, before slotting a decisive left-foot snap with seconds remaining to cap a 33-point comeback win for the Bloods against St Kilda in round 13.

Yet despite those headline performances, Serong identifies his moment of true belonging as a rain-soaked February day against Greater Western Sydney when he spent time on the opposite wing.

"It was the second practice match against the Giants at Henson Park where I played out of position on the wing," he told AFL.com.au.

"I felt like I had a decent game that day, and that gave me a lot of confidence to know that I can do it at the level. It was a really wet, tough day to be a winger, and I still performed."

The performance carried significance beyond the 38-point victory, reinforcing Sydney's belief that Serong could impact games away from defence and giving him the confidence to handle the positional shift at AFL level.

"Then my confidence just built over the year," Serong said.

"That game against West Coast was obviously a pretty good one, and we had a good day as a team. So, it just built over the year, and playing different roles helps with that. It's been really enjoyable."

The showing also strengthened Serong's case for a club debut in the season opener against Carlton a fortnight later. He has barely looked back since, missing just one game all season due to hamstring tightness in round nine.

Rather than pigeonholing him in defence, Sydney immediately embraced its trade-period vision, using him in difficult match-ups, intercept roles and stints on the wing and half-back.

"That's one thing I pride myself on; being able to play different roles," Serong said.

"There are a lot of different guys in the side doing that at the moment … that's something we pride ourselves on as a group - the ability to play a role. We feel like if we can all play our role to a high standard, we can do anything, and we're really confident.

"With the wing stuff, I played a little bit of wing at Box Hill last year, so I felt like I had a bit of a background there. But with the midfield stuff, that's been a bit of a change."

Serong's mid-season shift into an expanded midfield role opened a new dimension in his game, with the move accelerated by his work with Swans assistant coach Amon Buchanan.

"Coming in as a defender and adjusting to playing as a full-time mid, it’s been a really fun change of pace," he said.

"I've done a lot of work with Amon Buchanan, our midfield coach, on my craft in there. I'm really enjoying it; it keeps things fresh, and I'm happy playing anywhere as long as I'm in the side doing my role for the team."

When deployed in a run-with role, Serong’s value lies in his ability to curb the influence of opposition playmakers. According to numbers from Champion Data, rather than requiring a full game to wear down an opponent, he has consistently produced strong defensive outcomes in limited midfield bursts.

Having set an early benchmark by keeping established ball-winners Nasiah Wanganeen-Milera and Jason Horne-Francis quiet, holding both to 14 disposals apiece across full-game assignments in rounds 21 and 22, his shutdown impact became even more pronounced as the stakes rose. In the final weeks of the home-and-away season, he curtailed the influence of Zach Merrett (18 disposals) and Luke Davies-Uniacke (nine) in under an hour of game time, before restricting Josh Dunkley to just six touches in 41 minutes of qualifying final action.

But Serong's influence extends beyond negating opponents.

Across the final stretch of the season, he helped transform Sydney's midfield into a clearance powerhouse, generating a differential of +20.6 per cent, a measure of net clearances won versus lost while he attended centre bounces, ranking him among the League's most influential midfielders.

In fact, only Gold Coast's Matt Rowell (+22 per cent) recorded a stronger impact at centre bounces over rounds 21-27. Serong outperformed premier midfielders such as Fremantle's Hayden Young (+16.3) and Hawthorn's Jai Newcombe (+15.1) in net clearance percentage. Paired alongside Errol Gulden (+18.6), he gives Sydney two of the League's most influential centre-bounce players heading into September.

What began as a gamble on greater opportunity has become a career-best season. Serong's value lies not only in his versatility across defence, the wing and the midfield, but in his willingness to embrace whatever role the Swans require, giving Cox the flexibility to make key tactical adjustments during the finals series.

That journey now sets up a possible family midfield showdown with Caleb in Friday night's preliminary final against the Dockers.

The prospect adds another layer to a season that has already exceeded expectations, with Serong emerging as one of the clearest examples of Sydney's ability to identify and develop talent in new roles.

Should the clash eventuate, Serong has no plans to hold back despite family ties.

"I'm sure it will be a big occasion for our family and everyone involved with us," he said.

"But for me, Caleb is just another opponent, another game, and we'll prepare accordingly.

"Once we cross the line, there are no brothers out there. It'll be warfare."

While Serong views facing his brother in a preliminary final as a rare childhood dream come true, he is treating the occasion as business first and saving any family reflection for after the season.

"This year's been crazy for me personally. I didn't expect it to go this way," he said.

"As kids, you always dream of playing on the big stage against each other or with each other. Not many brothers can say that they’ve played in a prelim final against each other, so it is special.

"We'll reflect on that after the year, but at the moment it’s straight down to business."