The 65-year-old recalled how the country's international striker, Wynton Rufer, was playing for Central United that day.
"What I should have done was probably put Perry in the back ... although 2-nil is a pretty funny score," the retired Napier tiler said.
It was a toss up between Cotton, who went on to become an All White defender, and Ryan, who now lives in Wellington.
Also, the coach had rested Cotton and Wayne Atkins in the previous league match against Lower Hutt so he could put other players to the test for the cup.
Stanger, who was at the helm when the team won its maiden cup title in 1985 with Malcolm Wilson as co-coach, says he feels a little sad now that he recalls that day at Park Island although he had moved on since.
"Hopefully the players had gained experience and gone on to become better players," he says.
They sure did. Striker Marty Akers went on to play for New Zealand, too.
Centreback Dave Watson is now Stoke City physiotherapist in the English Premier League.
So what does Cotton make of it all?
The 48-year-old heating and air-conditioning engineer hastens to add he did grow as player, claiming two cup medals (2000, 2002) with coach Charlie Howe and was also assistant coach.
The former Kinetic Electrical Hawke's Bay United assistant coach says Stanger was fantastic and did what any coach would have done for the best of the team.
"1997 was the first conception of the summer league so guys like Marty Akers, Andy Rennie and I didn't want to play the whole year. We just wanted to play in the cup," Cotton explains, adding Ryan did commit all year.
Those who didn't play all year had their fitness under scrutiny in the 1997 cup final.
"I played senior fourths rugby for Havelock North and we went on to win the title so I was quite fit," he says with a laugh, adding the rugby club gave him the kicking duties as a fullback because of his soccer skills.
Asked if he was tired that day, Cotton says: "No, I wasn't. Chatham Cup is not about how good you play but about getting into the next round.
"You can play the best football and lose and no one remembers that.
"You just have to win the game, no matter how," he says, pointing out how teams go through on extra time and penalty kicks.
"It's a one-off game so you need the referee's decisions to go your way and little things have to go in your favour."
Going out with all guns blazing is great but teams mustn't get caught on the counterattacks.
Coming off the field having regrets about doing things differently, he says, isn't an option.
"When I came off the field I was always happy I had done everything and not be overawed."
The 1pm kick off for the Danny Wilson-captained Rovers tomorrow at Kiwitea Street should be electric, considering the Jose Manuel Figueria-coached side boast four Auckland City summer franchise players in Ivan Vicelich, John Irving, Takuya Iwata, of Japan, and Daewoo Kim, of South Korea.
Striker Emiliano Tade is also a franchise player in the Joseph Dawkin-captained team but he and goalkeeper Jacob Spoonley are not in the mix.
Central United are five-time cup winners while the Blues have four titles to their credit.
The two powerhouses have locked horns in two previous cup finals and have etched their names on the silverware once each.
But the Bill Robertson-coached Rovers are also having a stellar season.
They have lost lynchpin Andy Bevin who has returned to the United States to attend West Virginia University.
However, Welsh import Miles John returns from concussion and English import Ryan Tinsley and teenage striker Angus Kilkolly are back in the equation after sitting out their Lotto Central match against Petone FC in Wellington, which they lost 3-2.
Robertson decided to keep the pair on the bench because they are sitting on four yellow cards - one more and they'll have to serve a match suspension.
"The boys are pretty excited so we're looking forward to the game," he says.
While it isn't the ideal preparation for John, Robertson is satisfied the attacking midfielder has trained well and his technical nous will put him in good stead.
"Fergus is likely to be on the bench," he says of the attacking defender who injured his knee in his Canadian Premier League stint after leaving Rovers earlier this winter.
"He got injured in his first game and didn't play again."
Robertson says the Rovers have done their homework on Central United and were as prepared as they could be.
"Both clubs are big in New Zealand football and it's the semifinal so, no doubt, it'll be a great game.
With Figueira's credentials, Robertson expects and organised and disciplined team to take the park tomorrow.
While unbeaten at home this season, the Rovers will have to be at their best to book a berth in the cup final.
Figueria, 33, who was academy coach of Auckland City before he went to assume a similar mantle with an Major League Soccer club in the US, says he has NZ under-20 players in his mix.
"I say to my players to be creative and play a possession-based game with real purpose," he says, expecting about 1000 fans tomorrow.
Central were 3-0 down with 30 minutes to go in the third round against Birkenhead but won 4-3 with 10 men.
Figueria has tremendous faith in his players to embrace a philosophy that they should never think die, let alone say it, especially when the odds are stacked against them.
They were trailing Glenfield Rovers 1-0 in the fourth round but won 2-1 after losing men on the field.
He hastened to add Central United weren't physical or malicious but picked up cards where the goalkeeper breached his boundaries or through "innocuous decisions".
Figueria, who came from Crawley Town, West Sussex, in his early 20s to New Zealand, switched as player to coach five years later.
"I started my coaching journey because I saw some exciting opportunities so I chased them."
The New Zealand under-17 men's coach, who parents are Spaniards, started with Central United this year although he was the club's academy coach before heading off to the US.
He had also had a season as assistant coach with Auckland City.
MATCH DETAILS
WHO: Central United FC v Bluewater Napier City Rovers.
WHEN: Tomorrow, 1pm kick off.
WHERE: Kiwitea Street, Sandringham.
REFEREE: Campbell-Kirk Waugh.
AR1/AR2: Glenn Lochrie/Cory Mills.
CENTRAL UNITED FC: 1 Oliver Sail, 2 Faiti Hamilton-Pama, 3 Nick Dale, 4 Joseph Dawkins (c), 5 Adam Mitchell, 6 Takuya Iwata, 7 Jordan Roberts, 8 Dean Lausev, 9 Regont Murati, 10 Karl Reimann, 11 Mario Ilich, 12 Fabrizio Tavano, 13 Isaac Moffat-Young, 14 John Irving, 15 Ivan Vicelich, 16 Daewook Kim, 17 Adam McGeorge, 19 James Hoyt, 21 Finn Cochran, 24 Blaz Bugarin.
Coach: Jose Manuel Figueria.
Assistant coach: Paul Posa.
Manager: Phil Graham.
Physio: Alex Gairdner.
NAPIER CITY ROVERS: 1 Jonty Underhill (GK), 2 Josh Anstis, 4 Bayley Chadderton, 5 Bill Robertson, 6 Miles John, 7 Matt Hastings, 8 Stu Wilson, 12 Oli Chapman, 14 Josh Stevenson, 15 Ryan Tinsley, 16 Danny Wilson (c), 17 Fergus Neil, 18 Angus Kilkolly, 19 Phil Dol, 20 Chris Greatholder, Kyle Baxter (RGK).
Coach/player: Bill Robertson.
Manager: Malcolm Wilson.
Physio: Jono Henry.
Head to head:
1997 final: Central Utd bt Rovers 3-2.
2000 final: Rovers bt Central Utd 4-1.
2001 quarterfinal: Central Ut bt Roivers 1-0.
Rovers road to semifinals:
bt Taradale FC 2-1.
bt Wellington Olympic 5-4.
bt Palmerston North Marist 5-4 on penalties after scores tied 3-3 folowing extra time.
bt Tawa FC 4-2.
bt Island Bay United 4-1 in quarterfinals.