Watching a team fall to pieces in European soccer is unlike seeing an American sports club go bad.

The fall-into-ruin can drag out three months, easy.

In baseball, teams can blow big leads, and it may seem forever, but it generally is a month, maybe two.

In the NFL,  a collapse can be measured in three Sundays, 15 days.

Regular-season finishes don’t mean all that much in the NBA and NHL, so the notion of “losing something” (aside from playoffs position) is not really relevant.

Quite different, in soccer.

As evidence, I present the 2013/14 Arsenal Gunners of the English Premier League, who have been unraveling since … the middle of December. That’s nearly four months of unraveling, now.

Arsenal led most of the first half of the season. They held the ball, passed brilliantly, played decent defense, and they seemed to have a chance at a first league title since 2004 and a first trophy since the 2005 FA Cup.

Then came a game at Manchester City on December 14, and the Gunners got smoked, 6-3. It wasn’t quite as awful as the score seems because it was 2-1 and 3-2, and it got out of hand only because Arsenal kept attacking. But 6-3 … rather unsightly.

Then came a home 0-0 draw with Chelsea.

And the fade was in progress.

Mostly, it was about getting thrashed on the road by their rivals at the top. The 6-3 at City. The 5-1 at Liverpool. The 6-0 (!) at Chelsea.

The 3-0 at Everton, today.

Arsenal fans already had given up on the league. They had given up on the Champions League the moment they drew Bayern Munich in the round of 16. Already out of the league cup.

Leaving only two concepts worth pursuing: finishing in the top four and getting a Champions League place next season, which is in doubt with Everton now just one point back of fourth-place Arsenal, with a game in hand; and the FA Cup, which finds Arsenal in the semi-finals.

Now, most big teams don’t care all that much about the FA Cup, but Arsenal hasn’t won a trophy since 2005. So, yes, they do care.

Whether their rotting side can do so is the question.

They play Wigan at Wembley on Saturday in the semis. They ought to be able to win that, but they lost the league cup final to Birmingham City, for crissakes, a couple of years ago, and they have been so shaky of late … yes, absolutely, they could lose to Wigan. Unless they prefer to save the humiliation for the final, in May, when they could lose to the survivor of Hull City v Sheffield United.

As for the Champions League, which is crucial because it means tens of millions of dollars … Arsenal needs help.

They ought to win out in the league, against West Ham, Hull, Newcastle, West Brom and Norwich but, again, they have shown they can lose to anyone.

Meanwhile, Everton has two tough games left, home to Manchester United and Manchester City. If one of them can beat Everton, Arsenal in theory could still finish fourth and get the Champions League berth. Though their fecklessness in the face of any sort of adversity has left fans wondering about the players, as well as Arsene Wenger’s tactics, which seem to be entirely about holding the ball so as not to have to play defense.

It’s painful to watch. And it’s been going on a very long time.