Head coach Bill Belichick of the New England Patriots walks off the field a second before the Patriots lost to the New York Giants in Super Bowl XLII.

Getty Images / Streeter Lecka

PHOENIX — Bill Belichick preaches the team concept. It starts with him, he often says when his New England Patriots don’t play to expectations — he has to coach better, the team has to play better.

But on Sunday night at University of Phoenix Stadium, as his defense stood on the field for the last play of the season, Belichick was not on the sidelines.

He was headed for the locker room.

Now, the argument can be made that Belichick really didn’t miss anything: Eli Manning and the New York Giants’ offense simply lined up so Manning could take a knee and run the clock down to zero. There was nothing to coach, no special defensive formation to signal in to his players.

What Belichick did miss was the chance to stand with his players — his team, the one that he misses no chance to dress down nor remind that no one is more important as the whole — as they lost together, just as they had won together 18 times this season.

To many, Bill Belichick is a mystery. Even for some Patriots reporters, who have seen the coach four to five times a week for the last six-plus months, he’s an enigma. His outward demeanor is often dour and curt, his monotone voice giving emotionless answers to questions he’s asked about his football team.

Despite multiple stories of the 55-year-old’s generosity with lower-level coaching assistants, sticking cash in envelopes for them from the money he receives from radio appearances and the like, to the shots of him embracing his three children on the sideline after big wins, it’s easier for many people to dislike the slightly rumpled man at the podium for his public demeanor than believe that under that ragged gray hoodie there is a heart.

Yet, he can tell jokes, most of them self-deprecating. He can show enthusiasm during news conferences, particularly when he’s asked about coaching legend Paul Brown or his experiences as an NFL coaching neophyte in the late 1970s.

And he can coach football.

It was Belichick who kept New England focused enough, prepared enough, unified enough to complete the NFL’s first 16-0 regular season.

A master tactician renowned for his game-planning acumen, Belichick has said recently that he still enjoys coaching: the preparation, the practices, the games.

Clearly he enjoys the winning just as much, if not more. That’s not his sin. Every highly competitive person hates to lose. Tom Brady wants to be the first player in the Dana-Farber Fieldhouse behind Gillette Stadium when the Pats practice indoors. Michael Jordan would bet teammates on everything from cards to golf to whose luggage would appear on the baggage claim belt first (and bribe the agent to make sure it was his).

Competitive people thrive on winning; even those not as driven enjoy being on the winning side.

But regardless of how hurt he was by Sunday’s loss, how devastated he was by the realization that his team had won each of the first 18 games on its schedule but fell short in the one game that matters most, the one which he and Scott Pioli had retooled the roster to reclaim, Belichick did his team a disservice by not standing with them as the final second of Super Bowl XLII ticked away.

Ironically, when he was with the Vikings, New England receiver Randy Moss walked off the field with two seconds to play in Minnesota’s season finale loss against Washington three years ago; Moss was roundly castigated for his actions.

But Moss, much like Belichick, is a polarizing figure, and their negative behaviors draw greater criticism than similar behaviors put forth by better-liked individuals.

The coming weeks will be interesting and perhaps tumultuous ones for Belichick. There will be his annual scouting/fishing/baseball-and-lacrosse-watching trip to Florida, but there is also the looming specter of Spygate and brooding over undoubtedly one of the most difficult losses of his career.

He will huddle with Pioli to decide on a course of action for the team going forward, both with the players on the roster Sunday night, those available in free agency in three weeks, and the college players available in April’s draft.

Ultimately, the pair will make decisions based on what’s best for the Patriots.

Walking off the field, however, may not have been the right thing to do by Belichick’s players.

smanza@projo.com