Jim Harbaugh has been around football long enough to know the game's only promises are training camp, practices and a season that ultimately defines a team.

He also knows there is such a thing as a "good" loss or, at least, a "healthy" loss.

Harbaugh's 49ers experienced that last Sunday in Minnesota. They entered the game as kings of the NFL, and they left with precisely the message they had to hear and, moreover, needed to feel.

Fleeting is royalty bestowed by a now-is-all-that-matters society, for the NFL does not crown its kings until Feb. 3.

The 49ers surely had a rational grasp of this, but football is a game of emotion. Reality insists on emotion and rationale. San Francisco encountered both last week and will benefit from it Sunday at MetLife Stadium in New Jersey.

They'll also benefit from facing a lethargic New York Jets offense and a defense wounded and past its prime.

Given San Francisco's awakening, its first minicrisis of the season is one Harbaugh and his team ought to walk through.

The 49ers, after all, have had a full week to absorb an unwelcome development that was losing to the Vikings. They spent five days in Youngstown, Ohio, away from their families, living in a modest hotel in nearby Boardman and eating together.

Humility can be a powerful tonic. It also can stimulate the appetite.

"I'm away from my wife and kid, but at the same time there's no rush to get home, either," quarterback Alex Smith said. "So I can sit here and watch film and really dig into the game plan."

Not just the game plan, mind you, but also the urge to prove the real 49ers are much closer to what they showed the first two weeks, beating Green Bay and Detroit, than what they showed in Minnesota.

That's where Harbaugh comes in. This is where he does his best work.

The 49ers had spent the previous eight seasons alternately awful and mediocre when they opened 2011 by splitting the first two games. They won the opener and then lost at home to Dallas, allowing nearly 500 yards in the process. In only his third game as an NFL head coach, Harbaugh and his team were facing a defining moment.

Would they fall into old habits, residue from the days of Dennis Erickson and Mike Nolan and Mike Singletary?

Or would Harbaugh and his staff somehow authenticate themselves by building a level of camaraderie and trust and faith?

The 2011 49ers went to Cincinnati and won ugly, then spent a week in Youngstown before marching into Philadelphia and taking the pivotal game of their season. They won six more in succession, taking control of the NFC West before Thanksgiving.

Is there is more emphatic way for a new coach to authenticate himself than to win nine of his first 10 games, including the last eight in a row?

The 2012 49ers, by the way, are better and vastly more confident than the bunch Harbaugh had in 2011. The truly good coach, and Harbaugh is that, not only seethes but also seizes in the wake of surprising defeat.

"When you come off a loss, you want to get back to work and make darn sure it doesn't happen again," Harbaugh told reporters early in the week. "That's the mindset we have every day ... to work on that mindset in preparation for the game on Sunday."

This, then, was an opportunity for Harbaugh to reassert all the little things about which he had served warning. He referred to the past few days as a time during which the team would "circle the wagons."

That's where Harbaugh and his hands-on staff excel. They teach. They communicate. They laugh a little. They massage some egos, chip away at others. There is no need to shout, because their audience is both captive and receptive.

"What we believe in is pretty consistent," he said. "You go to work, find something to believe in and then go to work on that. And that's what we believe in, is preparation. It's going to put us in the best position possible to be successful.

"We go to work and we attack it. That's our message."

The coach realizes perfection is both the ideal and a myth. The 49ers were so impressive in the first two weeks that it opened the door to crazy projections. They never were going to go 16-0, much less 19-0.

But San Francisco remains the favorite to win the division, even with Arizona's torrid start -- even with Seattle's fraudulent win last Monday night.

Though Harbaugh certainly didn't welcome defeat, I'd guess he knows what's bad for the record can be good for the season.

Contact Monte Poole at mpoole@bayareanewsgroup.com. Follow him on Twitter at twitter.com/1montepoole.