NEW ORLEANS —On the last Sunday of 2012, the New Orleans Saints defense went from bad to worst in the history of the National Football League.

The Carolina Panthers stuck an exclamation point on an already horrific season by the Saints defense, amassing 530 yards in a 44-38 victory in the regular season finale before a sellout crowd of 73,124 at the Mercedes-Benz Superdome.

The Panthers’ onslaught included 273 yards on the ground — 210 on 21 carries alone by running back DeAngelo Williams — and five rushing touchdowns. Williams scored on runs of 54 and 12 yards, and Mike Tolbert chipped in with three scores each from 1-yard.

The Saints (7-9) allowed the most yards in a single season (7,042), moving past the 1981 Baltimore Colts (6,793), the 2011 Green Bay Packers (6,585) and the 2011 New England Patriots (6,577) all in one afternoon.

Afterward, Saints officials reported no game-related injuries, but there were plenty of bruised egos visible in the locker room.

“The season has been just like this game; we played terrible,’’ Saints strong safety Roman Harper said. “Even when we gave ourselves a chance there at the end of the game, we do like the dumbest things ever, the same stupid things that got us beat all year.

“Penalties. We didn’t stop the same guy (Tolbert) on the goal line three times. We gave up long third downs. It’s the way it’s been all year. Just awful. Man, I’m just glad this season is over.’’

When asked his reaction about setting an NFL team record for most yards allowed in one season, Harper replied: “If you’re shocked that it happened, then I don’t even know what you’ve been watching this season. The game is just that, man. It’s a bad way to end the year.’’

Saints linebacker Jonathan Vilma produced one of the few bright spots on defense, returning an interception 18 yards for a touchdown and a 14-10 Saints lead with 4:31 remaining in the first half. The Saints extended their lead to 24-13 in the third quarter before the Panthers scored 28 unanswered points to sweep the season series.

“You get what you deserve,’’ Vilma said of the NFL record. “You don’t play good defense, that’s what’s going to happen. Be a man and suck it up.

“Some games, we played lights out. Other games, we’ll give up 44 points (and) who knows how many yards. You can’t win like that in this league.’’

Sunday’s poor defensive performance came just two weeks after the Saints scored their first shutout in 17 years, a 41-0 shellacking of the Tampa Bay Buccaneers at the Superdome. And, it mirrored Carolina’s 35-27 victory against the Saints earlier this season, when the Panthers amassed 463 yards, including 219 on the ground.

In two games against New Orleans, the Panthers scored 79 points and produced 1,007 yards, including 492 rushing yards.

“This year has been like no other year I’ve ever had,’’ said Saints middle linebacker Curtis Lofton, who opted to leave the Atlanta Falcons during free agency and sign with the Saints. “Right now, I don’t know how to feel about anything.’’

Saints defensive end Will Smith shared Lofton’s sentiments while cleaning out his cubicle for the last time this season, and perhaps, for the last time as a member of the Saints.

Smith, who won his court fight to overturn a four-game suspension for his role in the bounty scandal, is scheduled to make a base salary of $9 million in 2013, plus a $1 million roster bonus in March.

“I’m not happy the way the season has ended because we strive as players to make it to the Super Bowl,’’ Smith said. “We wanted this to be a special year. We wanted to be the first team ever to play in a Super Bowl in its hometown.

“So from that perspective, I’m very disappointed and very sad that we’re not in the postseason to have that opportunity. But, on the flip side, it’s good to have the season over with so now we can finally put all this garbage behind us and move forward to next season.’’