Humble as they are when empty, when filled with the inner sanctum of a professional football club, they dramatically buzz to life.

We can delude ourselves about the importance of everything else - sponsors, TV, crowds, money, status, fame, the media - but in here, that matters nought. This is where it really happens.

And once you walk through that door, your ego must give way to the collective. In this place, the greater good rules all.

The thought immediately strikes me: this is why retirement among some is so utterly terrifying. Where else in society can one find the pure rush of adrenaline and camaraderie against a backdrop of brute competition and pure physicality?

For one night only, in their annual game against Macarthur Rams at Campbelltown Stadium, Graham Arnold has invited me to witness it, warts and all.

There are no sheep stations on the line tonight but Arnold will be keen to see where his players are at after a few weeks of pre-season.

Outside, it’s assistant coach Steve Corica taking care of the drills. He doesn’t say much, pausing only to maintain standards. “Keep it sharp,” he barks after a stray pass. “Boys, focus!”

On the sidelines, Sydney’s youth coach, Robbie Stanton, has a private word with Rams’ boss Lee Sterrey.

As they split up, Stanton says “Just enjoy it tonight,” - to which Sterrey, one of the great characters of the lower leagues, cheerfully shoots back: “When don’t you enjoy it?”

The players come in and Arnold has the starting eleven on the seats in front of him. His tactics are simple but the instructions are minutely detailed.

On the whiteboard, it’s a 4-3-3, but not a traditional one. And if the players do their jobs correctly, it’s almost a 3-4-3 in attack and a 4-5-1 in defence.

It’s only here that one learns how different tactics are in theory and reality. Formations, in public discourse, suddenly seem finite and outdated.

Modern coaching is infinitely more fluid. It is much more about collective strategy and individual roles.

Without giving too much away, Arnold is big on rotations, overlapping and stacking. He wants to create numerical advantages all over the pitch - a hallmark of his halcyon days at Central Coast.

The strategy is sound. The only worry is whether the new players are tactically savvy enough, not to mention fit enough, to implement it.

The starting line-up is a mix of youth and first team, without a number of key players including Alex Brosque, Milos Ninkovic, Bernie Ibini, Matt Jurman and Michael Zullo.

Traffic chaos on the M5 has cost Rhyan Grant and Filip Holosko their spots in the starting eleven. Arnold picks Bai Antoniou at left-back and Young Socceroo William Mutch at right-back - a test to see if they can cut it at this level.

As the speech winds to a close, Arnold acknowledges that Macarthur will be playing for their lives.

“This is their opportunity to perform. It’s one night only for them and they will do whatever it takes to make it difficult for us,” he tells the team right before they run out. “But we have to be much better - mentally - than that. From the first minute to the last, I want to see a professional display from everyone in a Sydney FC shirt.”

Hardly Any Given Sunday, but nor should it be. Those will come, all going well, next May.

At such close proximity to the players, you notice their idiosyncrasies: Alex Wilkinson’s tiny shinpads are taped to his calves. Matt Simon mixes a languid manner with a frightening stare. David Carney is so relaxed he could fall asleep. Rhyan Grant - a notorious joker on the training track - is pure focus despite his late arrival.

They run out to a small but boisterous crowd. So small you can hear the individual voices - and at least half are supporting the underdog.

There’s a table oddly positioned next to Arnold’s seat on the touchline.

“What the hell is this here for?” he asks Sterrey. The reply: “I thought we could have half-time tea and scones.” Both share a laugh of familiarity. They coached against each other for the first time almost 20 years ago.

The match kicks-off, and it’s jarringly apparent that Macarthur can’t get enough players behind the ball. “Is that six at the back?” asks strength and conditioning coach Andrew Clark, half-kidding.

Arnold pipes up to the opposing bench: “Lee, you’ve haven’t just parked the bus, you’ve put up a block of units!” On the evidence of the opening ten minutes, he’s not wrong. The Rams know their limitations.

The freezing winter cold has its first victim. Milos Dimitrijevic, who Arnold had urged to play an unusually high role as soon as the Rams sat deep, has an ankle complaint.

Seated to my right, physio Elias Boukarim sprints out to attend to the situation. But the Serbian midfielder waggles his finger dejectedly. He’s coming off.

A quick decision has to be made - nobody was expecting this. Grant, ever reliable in every role, comes on.

New signing Josh Brillante is making an immediate impression. He links the play smartly; most good things happen through him.

Still, his combination with Brandon O’Neill needs work. Such a classy player on his day, O’Neill is a little off the boil. Both he and the coaches know it. The bumpy pitch isn’t helping him.

Sydney continue to dominate but there’s a disjointedness to their play that’s bothering Arnold. He hammers his men to press and press again. They try, but it’s half-hearted.

In particular, the coach is riding Matty Simon. The striker is mis-timing his runs and it’s driving Arnold - one of the nation’s greatest ever strikers himself - to despair.

“Pull the trigger Simmo!”

“Press, press, press, Simmo! Press!”

But knowing their history, I see it's only because Arnold badly wants Simon to succeed And he knows Simmo can handle a bollocking, too.

The boss is also at the wingers, David Carney and George Blackwood. They’re drifting inside to seek the ball but with Macarthur having stacked the area already, Arnold wants them to stay high and wide. Arnold even sends Clark to the far side of the field just to tell Blackwood.

Ahead of his 500 metre return sprint into the winter’s night, Clark shoots me a priceless look that says: ‘And you thought this was a glamorous job’.

Arnold soon does away with Blackwood out wide, instead trying him in the number ten role. The young striker tries gallantly but finds it difficult to play in what little space is afforded him.

On my left is John Crawley, the revered goalkeeping coach. He makes a fastidious set of notes - but is the first to recognise when an opponent is moving unchecked into space. His booming voice ensures the player hears it, too.

Crawley and Vedran Janjetovic communicate in their own language, a combination of shouting and sign. For the first time in several seasons, the arrival of Danny Vukovic means nothing is assured for Janjetovic. They get 45 minutes each tonight.

An inspired run from Rams’ forward Mason Versi, who has spent time with the Central Coast Mariners youth team, leads Crawley to whisper in my ear: “Watch this kid, he can finish”.

Half-time arrives and Sydney still haven’t scored. They’re not playing well, but they are dominating possession.

Arnold permits his side an alternate plan to find a way through - the defenders can play long if required, but only if they are clever enough to manipulate the space first. No hit-and-hope balls.

But what Arnold hasn’t spoken about - understandably - is that Macarthur might score. Besides, there has been no real indication of it. Yet three minutes into the second half, that’s exactly what happens. And it’s Crawley’s words that ring true.

Our vantage point is obscured as the ball is crossed into the box but we get to see Versi make a clean finish from close range.

Having come on at half-time, Vukovic’s first act in Sydney FC colours will be to pick the ball out of the empty net.

There’s very little concern on the Sydney bench about conceding. They can dissect that in the post-match review. For now, it’s about finding avenues to goal.

Holosko has come on and is adding something down the right, while Blackwood comes off in a state of fury. He spent the first half finding his rhythm and has now hurt his groin.

Defender Seb Ryall is also off and is complaining about being kicked on the back of the heel. It’s only minor, but that’s three men down in the first hour.

Macarthur are growing into this game but it’s still hard to believe they’re in front. One midfielder has a glorious rat-tail, the type you could only grow in Campbelltown. Their left-back looks like a dead ringer for Sonny from Grease. They’ve just brought on an attacker so young he looks like he’s come from the under-14s.

Sydney burn more chances. It’s clearly not their night. With 20 minutes to play, Arnold brings off Wilkinson, O'Neill, Brillante and Carney, replacing them with four teenagers of his own.

Time has raced away from the Sky Blues. With a few minutes to play, the players are urged to get the ball in the box as quickly as possible. Simon, still bustling away, is desperately unlucky not to level things up.

It’s 89:58 on the clock when the referee blows for full-time. I’ve never seen that before. The Rams are unlikely victors; they’ve not beaten Sydney in seven previous attempts.

The rooms afterwards are relatively muted. Blackwood and Dimitrijevic are both getting treatment, with the latter confirming to Arnold he “felt something” but that he’ll be fine. "Don't worry, no problem".

There isn’t too much to be said by the players to each other, nor from the coaching staff. Their professional pride has been dented.

Captain Brosque is in there, likewise the rest of those who didn't play. They know how is important it is to stick together, especially in defeat.

Nevertheless, it’s only a pre-season practice match and after a grueling few weeks of double-training sessions - including a full game only the day before - the heavy legs of many have an alibi.

Chief executive Tony Pignata and club chairman Scott Barlow have now arrived for moral support, sufficiently rugged up to stave off the winter chill.

I’m invited to eat with the team, and despite trying to give the players space given the result, Wilkinson, Simon and football manager Terry McFlynn have joined me for time-honoured tradition of chicken and pasta.

The two teams eat side by side, with the local association president making a short speech praising the connection between the two clubs, which Pignata reciprocates. It’s a nice touch - you won’t see this in the A-League.

But there’s none too much chatter from the Sky Blue tables. Losing, even in pre-season, hurts. It will be a long trip back to the city.