The New Orleans Saints never imagined that clinching a division title could be so humbling.

Coach Sean Payton was still searching for answers after watching game film Monday. He was wondering what could have caused the Saints to look so lethargic on Sunday when a victory would have set them up for a remarkable postseason berth with their home fans in a sold-out Louisiana Superdome.

The Saints, who came in with top-ranked offense in the league, managed only 10 points against the underdog Washington Redskins and were held to under 300 yards on offense for the first time this season in a 16-10 defeat.

New Orleans (9-5) clinched the NFC South anyway because Atlanta and Carolina, the only teams that had a chance to catch the Saints going into this week, both lost.

“It’s just tough to do that on a bad note,” said Payton, who often speaks affectionately about Saints fans and has been known to celebrate home victories with them before heading to the locker room. “The frustration was, it had a chance to be a real special day and we didn’t play well at all, so it was hard to get excited about the other accomplishment.”

Payton had seen his team do so many things right in this surprising, feel-good season, that he was simply dumbfounded by his team’s sluggishness.

They weren’t just struggling on offense. New Orleans gave up 161 rushing yards, while allowing inexperienced quarterback Jason Campbell to throw for 204 yards and a touchdown.

“The mistake would always be just saying, ’You know what? We just played poorly so let’s go on to next week,” Payton said. “It’s important as a coach to evaluate, maybe, why is it that it wasn’t just one area? We were pretty sluggish in a lot of areas. I didn’t think we had much energy. And that was a great opportunity to come play with energy, considering the game being here.

“We’ve played some games where we’ve lost and had some turnovers or given up some big plays, but this was the first game that I felt that we were sloppy, sluggish and lacked a little bit of the hustle and effort and energy you expect,” Payton said.

The Saints had a light schedule on Monday. The locker room was mostly empty as players wandered in and out between lifting weights, running, or getting treatment in the training room.

The sales office just inside the main entrance to team headquarters was much busier, as a steady flow of fans bought playoff tickets.

Looking at the season as a whole, the Saints have very little to be ashamed of.

It was considered a minor miracle that they were able to return home and play in the rebuilt Superdome one year after Hurricane Katrina devastated New Orleans.

Residents eager to embrace a symbol of recovery sold out the Dome for the entire season before one home game had been played.

For the most part, fans have been rewarded for their loyalty in ways never expected. After the Saints went 3-13 last season, they were picked by most prognosticators to finish last in the NFC South. Instead, they will host at least one playoff game.

The Saints need only to finish even with Dallas (9-5), Philadelphia (8-6) and Seattle (8-6) to retain the No. 2 seed in the NFC and the first-round bye the goes with it.

New Orleans got in this position of strength with a 42-17 victory at Dallas two games ago. But they can’t afford to play like they did against Washington.

“After the Dallas game, everybody blows smoke about how great you are. This brings us back down to earth, to understand and realize we’ve still got work to do,” Saints running back Deuce McAllister said. “It’s time to refocus and get our minds right for what we really have to do if you’re going to make a run. All of our goals are still obtainable. We still have everything in front of us as a team.”

One ironic trend this season of happy returns is that New Orleans’ home record (4-3) is worse than its road record (5-2).

The Saints visit the Giants on Christmas Eve and expect New York (7-7) to play desperate football. But the Saints are hardly acting like the pressure is off of them simply because they’re already in the playoffs.

Payton pointed out that the only time he went to a Super Bowl as an assistant coach was with the Giants in 2000 when they had a bye. And he believes having a bye improves the chances of winning a title, even though Pittsburgh did so without a week off last season.

“Coach Payton — he was talking about raising your expectations,” McAllister said. “You see what type of team that you have, so why just settle for getting into the playoffs.

“I want to play more than one game. I don’t want to be one-and-done,” McAllister continued. “I’ve never been there before, so you want to make that feeling last a little bit. You want to go in on a roll.”