The All Whites' main playing unit relied on tough professionals from all sorts of levels and backgrounds.
None though have gone close to the heights of Nelsen, a key defender and club captain of Blackburn Rovers in the English Premier League.
From this high sporting altitude, Nelsen says he has learned about attitude.
Nelsen is such a convert to the power of sports psychology that he has invested in the firm Provelop that specialises in analysing and developing sports mindsets and mental toughness.
He discovered the programme just after the All Whites qualified against Bahrain and says among other things, he discovered he was good at learning from the best but not in assisting players from lower levels.
He set about changing his ways, and then his teammates' mindset.
The numerous ploys included a jovial press conference act at complete odds with the stress which was to lay him low before the final game against Paraguay.
Nelsen also rubbished opponents he knew nothing about during team video analysis sessions.
He took one of his cues from a former American club mate, the Bulgarian Hristo Stoichkov.
"I remember Hristo joking around before a playoff game," said Nelsen. "It had a big impact on me ... confident and relaxed people in any high-pressure environment put you at ease.
"I found out the interviews the day before the World Cup matches were fed directly into the team bus where the boys were waiting.
"So I tried to be as laidback as possible, even joking ... it has a subliminal effect if you see your leader like that. We wanted them so relaxed and confident against so-called world-class players, so they were thinking 'well I'm a world-class player too'.
"One of the media guys, Gordon Irving, actually approached [manager] Phil Warbrick about getting me to be more serious."
Nelsen wanted his underdogs to "strut".
"We couldn't be the typical New Zealand football side walking out feeling like four foot four - we had to be seven foot four.
"It was hard to win [New Zealand Football] people over to get the mentality right but the players were fantastic. We had strong personalities which helped."
Nelsen noticed many players were initially in awe when the video analyst Chris Bradley portrayed how good opponents were.
"So I would say that I knew the players were rubbish, that I'd seen the guy in training and he was hopeless, that I'd rather have my guys than him," said Nelsen.
"Actually I hardly knew any of the players I was rubbishing.
"Each time you might increase a guy's confidence by a fraction, but do that 10 times a day, over 10 scenarios, and spread over a team it can mean the difference between winning and losing."
After the tournament Nelsen returned to America where his wife Monica was expecting their second child.
Then it was back to the pressure-cooker world of the English Premier League, but the World Cup was never far from his mind.
"It was an incredible experience, but I've got to admit my only enjoyment was during the 270 minutes on the football field," he said. "Everything else was stressful and I took a massive hit. We were in an elite environment, and with no disrespect to New Zealand Football they don't understand that world.
"After I got back home the body shut down. Since the moment we qualified, this was all I had thought about. What with things on the field, the fires you have to put out, all the worrying about the whole squad ...
"Guys like Simon Elliott who understand that elite level were critical to our success and so was Phil Warbrick, who is in the elite business world.
"Those guys were incredible, and there were so many instances when the rest of the players didn't even know what we were doing behind the scenes.
"The main satisfaction I got was hearing back what happened around the country. Everybody jumped on board and felt really proud.
"The fans rode the wave and I don't think anyone expected us to do what we did, even in their wildest dreams.
"Many New Zealanders won't realise the impact. I still get interviewed about it ... Italian fans even yell abuse at me after Premier League matches.
"This will live on and New Zealanders can't comprehend how this game is a religion around the world."
He called on the NZF board to fork out for the best possible chief executive to replace the departing Michael Glading.
"The NZF needs strong leadership [to take advantage] now. For me, this is the one thing that is weak.
"They need a leader who can organise, been around, knows the ropes, who people can learn from.
"We're talking force of personality, charisma ... which is the same in any business.
"NZF is now one of the strongest sporting bodies financially and should pay to get the best whether that person is in New Zealand or elsewhere if necessary. That's just my humble opinion on it."
THE MATCHES THAT BROUGHT THE NATION TO A STANDSTILL
SLOVAKIA 1-1
Royal Bafokeng Stadium, Rustenburg
We stressed during the pre-game talks that games aren't won over 90 minutes, they depend on split-second decisions. Did you track back even though you were buggered? Those kinds of decisions. The game will go in the blink of an eye, and those split seconds will determine how well we do. Only the players themselves can know if they made the right decision - no one else can point the finger because they don't really know. A 10-second, five-second, two-second play when we scored changed everything.
Slovakia were only playing one up front and in about the 83rd minute, with Slovakia leading, I sent Winston Reid forward. From there the decisions were up to him. Winston is so athletic, he's quick and has a fantastic leap, he's powerful, and he was the right person.
I was thinking about going forward myself, but the old knees aren't the best and sometimes it is better when you are young and naive and fearless. Shane Smeltz chased a guy, pushed him off the ball - he was too strong for him and he wanted the ball more. He knocked him off it, boom, won it, cross, Winston's header, goal. That was just incredible - to do it in the 94th minute showed the character the boys had.
Simon Elliott, at 36, did more running than anyone and he was incredible in that game, his best game. What I loved about this team was that on the highest stage, they maximised their performance. That was the coolest thing about this team - every one of them played to their best, which is a very special thing to do.
ITALY 1-1
Mbombela Stadium, Nelspruit
It's funny how greedy you can become - the goal we conceded against Slovakia was offside, and the one against Italy was a soft penalty. We go 1-0 up, get a very dubious call against us, and everybody expects Italy to go on and win by three or four to one. Not so. Mark Paston pulled off saves I don't think many keepers in the tournament would have made.
I have to admit that before the Bahrain games, I said to Simon [Elliott] I thought goalkeeping would be our Achilles' heel. Glen Moss was out and Mark had been injured. When he came back he had a pretty average game against Jordan.
You need a goalkeeper who can pull off a world-class save at this level. Boy, did Mark prove me so wrong against Bahrain and in South Africa. For a guy who has been around so long, through some really bad times, it was incredible to see him perform so well.
You could sense Italy's frustration and that drives you on. They actually didn't throw caution to the wind in the last 10 minutes. They didn't throw three or four players up - they were scared it might backfire, a real credit to our boys.
The game kind of petered out in the last five minutes. Little did they know we were absolutely exhausted - one more attack would have given me a heart attack.
I don't really look at my own performance - I'm a bit too old for that, had too many bad games. So long as the team plays well and you get the results. Tommy Smith and Winston Reid were fantastic at the back - they are young and they listen.
PARAGUAY 0-0
Peter Mokaba Stadium, Polokwane
If I do have one regret, it was not being 100 per cent in the last game. A real bad stomach virus killed me and I was probably already fatigued from worrying about the whole squad.
I felt we had some control of our destiny at the end against Slovakia, but didn't have the same mindset in the last 15 minutes against Paraguay [by that stage the All Whites knew they needed a goal to progress in the tournament, because of the score in the Slovakia-Italy match].
I wouldn't have played if it was a Premier League game - the manager wouldn't have let me. When I was selected for drug testing the doctor took one look and said "take him away because I won't get anything from him". He put my name back and picked out another guy, Rory Fallon. I don't even know if that is legal.
I could hardly remember my own name, let alone figure out a soccer chess game and the moves to win it. I was trying to tell our three strikers to stay high and let them break on us. I think our guys were a wee bit too honest and didn't understand what was going on, which was my fault. Our two wide strikers were tracking back to cover their left and right backs. I was trying to tell them to let it go - to encourage Paraguay to come forward to help us find a goal. It is a wee bit of Russian roulette at times and you can defend your box with small numbers if you are organised. Poor Jeremy Brockie - for three years he heard me screaming to track guys back, and now I'm screaming at him not to track his guy. History says three draws at the World Cup is pretty amazing, but ...
