Deplorably, this is the way things work in soccer: When the going gets rough – the rough get going. For all the attempts to turn soccer coaching into a sophisticated science, for all the reverence now afforded to coaches, their basic resource, when they’re desperately in need of a win, is simply to get physical.

The English have a lovely term for this. They call it getting “stuck in,” a suitably primitive wording that shears away any thoughts of skill, or any notions of good soccer.

On Sunday, at Manchester United’s Old Trafford stadium, ManU got stuck in against Arsenal and were rewarded with a 2-0 victory that put an end to Arsenal’s amazing 49-game unbeaten streak. It was not a pretty game. It was – to use some of the adjectives appearing in the English press – fractious, scrappy, heated, spiteful, ugly, unsportsmanlike, a game of “simmering ill-will.”

The hostilities continued outside the locker rooms after the final whistle. It seems that a cup of hot pea soup, launched from the Arsenal group, drenched ManU coach Alex Ferguson.

In an inflammable game – and the recent Arsenal-ManU clashes have certainly been that – the role of the referee is greatly magnified. Arsenal coach Arsene Wenger had plenty to say about that.

While not quite accusing referee Mike Riley of bias, he pointed out that in his previous seven games refereeing at Old Trafford, Riley had awarded ManU a penalty kick in every game. Riley duly made it eight out of eight by calling Arsenal defender Sol Campbell for tripping Wayne Rooney. Ruud Van Nistelrooy scored from the spot – the crucial first goal.

Arsenal denied that it was a penalty kick – they would, wouldn’t they? – later claiming that Rooney had boasted to them that Campbell never touched him. Television replays appeared to confirm that it was a bad call.

Wenger did not mince his words in condemning ManU’s approach to the game. Rooney, by implication, was damned as a cheat. But Wenger was even more incensed by the rough treatment handed out to his Spanish winger Jose Reyes, accusing ManU of trying to “kick Jose Reyes off the field.” The overly physical play came as no surprise, Wenger said, because “that’s what they always try against us when they’re in a difficult situation.”

No, it would not have been a surprise. Because the get-stuck-in approach shown by Ferguson and ManU is deeply entrenched as conventional soccer wisdom.

There is clearly some discomfort among the coaching fraternity about the crudity of this game plan. They try to disguise its banality and its brutality with euphemisms. On the day of the game, former Arsenal coach George Graham, writing in The Observer, offered this carefully-worded advice to ManU: “You roll up your sleeves and try to beat them in terms of effort and commitment. If being disruptive upsets their passing and movement, that’s what you have to do.”

Being disruptive, you’d think, is what any defense must do to the opposition in any sport. But it has a hidden meaning in the soccer context. It means a thoroughly cynical approach to the rules of the game. It means tactical fouling. As soon as an opponent looks like he’s going somewhere with the ball, trip him, or hold him or pull his shirt, or somehow get in his way.

Do all of that systematically, and make sure you do it in the midfield area where the resulting free kick is not likely to set up a goal-scoring threat.

A glaring display of this apparently praiseworthy disruptiveness had been seen just one day earlier, right here in Giants Stadium, in Saturday’s playoff game between the MetroStars and DC United. This rivalry, while hardly at the fever pitch of the ManU-Arsenal clashes, does have quite an edge to it.

It is a rivalry that DC has been taking rather seriously of late. This marked the third meeting of the two clubs in the past three weeks, and in all three DC has out-fouled the MetroStars by wide margins: 26-12, 24-16, and 23-16. DC’s reward for this disruptiveness has been to win all three games.

DC’s novice coach, Peter Novak, did not start the season well. His team looked incoherent and he carried the burden of figuring out how to handle teenage phenom Freddy Adu, whether to use him as a starter or as a sub or whether to play him at all.

Things are looking up now. Following the 2-0 win on Saturday, DC is in a commanding position in its two-game playoff against the Metros. The two meet again on Saturday in Washington. The aggregate score of the two games decides the tie, making DC the heavy favorite to advance to the Eastern Conference final – just one game away from the championship game.

Novak has an explanation for DC’s turnaround: “During the season I told my team that winning is about running and fighting, not just soccer. That is why we have been winning, and lately we have been able to play soccer, too.”

Novak’s running and fighting closely resemble George Graham’s effort and commitment. And disruption rules. MetroStars coach Bob Bradley was much calmer than Wenger, but he basically had the same complaint: “We saw it last time DC played here, where they foul to break up plays, where every time [Amado] Guevara tries to create something he is brought down. I’d like to see the referee more on top of that, he needed to issue cards earlier in the game.”

Bradley now has to decide how to approach Saturday’s crucial game. Trying to play skillful soccer against DC’s tactical fouling has not been successful. Must Bradley, with one eye on DC’s 73-44 lead in fouls committed over the past three games, now adopt the get stuck-in approach?

A decision to take that route would be both understandable and lamentable. The major casualty would be good soccer. Novak’s claim that DC United has “been able to play soccer” lately is already debatable.

Despite the promise of Adu, despite the brilliance of Jaime Moreno and an occasional sparkle from Alecko Eskandarian, DC’s performances rarely rise above the efficient category. The running and fighting, to say nothing of the fouling, have been the most noticeable feature.

Add a MetroStars team also intent on disruption to that mix and the outlook for good soccer looks bleak. I doubt things will reach the pea soup assault level, but chances are high that Saturday’s game will be more about aggression than soccer.