Some of the game's biggest names will be honoured on Thursday when the Greatest New South Wales team of all time is announced at a gala function in Sydney.

NSW has produced seven Brownlow medallists, five Magarey medallists in the SANFL, and three Sandover medallists in the WAFL, along with hundreds of other greats over the past 140 years.

AFL.com.au's Sydney reporter Adam Curley spoke to one the state's finest products, Sydney coach John Longmire, about the most significant night in the history of NSW footy, when the underdog Blues did the unthinkable.

When the star-studded Victorian state of origin side arrived in Sydney to take on the footy minnows of New South Wales in 1990, they brought all their arrogance and swagger.

A team containing greats such as Stephen Silvagni, Dermott Brereton, Dale Weightman and Paul Salmon expected an easy Tuesday night at the SCG.

What they copped was a reality check.

Torrential rain greeted the Vics that afternoon and by the time the ball was bounced, the conditions weren't much better.

All the talk pre-game had been about the 'Big V' and how much they'd embarrass the local boys coached by Col Kinnear, and there were even some Victorians playing for the enemy thanks to some loosely enforced selection policies at the time regarding origin rules.

But the visitors didn't count on the state pride of NSW players such as the Daniher brothers – Terry, the team captain, Neale, Anthony and Chris – who were playing together for the first time, or North Melbourne teenage prodigies Wayne Carey and John Longmire.

"There's no question we were the 50-1 chances and rank outsiders," Longmire recalled to AFL.com.au this week.

"The way we saw it there was no pressure on us and it was a great opportunity to play the best in the game.

"Victoria fielded a very strong team and we just went out and enjoyed it."

A stirring speech from the skipper Daniher didn't seem to inspire his players as Victoria eased its way to a five-goal lead midway through the second term, and the Melbourne media had already begun to write their headlines hailing the footy powerhouse.

Enter the booming boot of Longmire, who had 33 goals from his first eight games with the Kangaroos that season, including a haul of 12 against Richmond to kickstart his year in round two.

"I distinctly remember that second quarter, we got on a roll and things were going our way, and for a period there everything we tried worked," he said.

At the time, Channel Seven broadcaster Bruce McAvaney was full of praise for Longmire's performance as the home side fought back to be in front at the long break.

"You'll have to go a long way to ever see a better half of footy," he said.

The Vics mounted a charge as the NSW boys knew they would, but another Longmire major 23 seconds into the last quarter helped them hold on to a 13.8 (86) to 10.16 (76) victory.

It was a monumental effort and still one of the greatest upsets in the history of state footy.

''Winning tonight for NSW was tremendous and one of my biggest thrills in football,'' a young Longmire said at the time.

The Blues' win was made even sweeter by the fact – or fiction – that some of the players had backed themselves at extraordinary odds to walk off the ground victorious.

"I can't recall that but I'm not denying it happened, I might have been too young," Longmire said with a laugh.

It may have happened almost 30 years ago, but Longmire and his NSW brothers haven't forgotten the significance of what the underdogs achieved on a wet Tuesday night at the SCG.

"Wayne Carey and I played for NSW in Darwin in the under 12s and came up playing for NSW as juniors, so to be able to represent our state at senior level was a fantastic experience," he said.

"The memories of that night are something we still treasure and every time we catch up with the guys from that team, you realise the special bond we have.

"It was such a unique part of football history and something we're extremely proud to have been a part of."