The Saints season no one saw coming is headed to the playoffs. 

New Orleans, ignored by preseason prognosticators and left for dead after an ugly start, clinched the berth with a win over the hated Falcons.

Backed by a raucous, angry Superdome crowd out for Atlanta blood, the Saints exacted revenge on the Falcons in a dominant 23-13 win that sealed New Orleans' first playoff birth since 2013. 

With the win, New Orleans only has to beat Tampa Bay in the season finale to earn its first NFC South title since 2011. A final-minute comeback by Carolina against the Buccaneers on Sunday allowed the Panthers to keep pace with New Orleans. 

"(The playoffs) are kind of further down the road right now," Saints coach Sean Payton said. "We're looking at how to win this division. It sounds like we were close, but we're going to have enjoy this next 48 hours and then get refocused."

The Saints (11-4) have played their best football when their back was against the wall this season. New Orleans responded to back-to-back blowout losses against Minnesota and New England by ripping off eight consecutive wins, and when the Panthers had a chance to take back control of the NFC South right after the streak was broken, New Orleans crushed Carolina in the Superdome.

New Orleans found itself in another pressure situation on Christmas Eve. As good as the Saints have been all season, Atlanta and Carolina have been able to keep pace, and New Orleans entered Sunday's game knowing that a loss and a Panthers win would eliminate the Saints from NFC South contention. 

And the bad taste of the first matchup against the Falcons (9-6) this season turned up the heat to the boiling point. Two weeks ago, New Orleans lost a penalty-marred, injury-plagued game in Atlanta, an affair that produced a dust-up between Payton and Falcons running back Devonta Freeman, as well as open criticism of the officiating. 

"We've overcome a lot, especially early on when all of you guys were asking us about another 0-2 start," Saints quarterback Drew Brees said. "Here we are, poised to win the division."

New Orleans responded by grinding Atlanta into dust. 

A resurgent Saints defense led the charge. Bolstered by an influx of talent this season, New Orleans has left its awful defensive reputation behind this season, but the Saints have also struggled against the run, and Atlanta entered Sunday's game averaging 145.8 yards on the ground over its last four games.

New Orleans walked into the Superdome knowing what it would take to slow down the Falcons.

"We had objectives that we needed to accomplish," defensive end Cameron Jordan said. 

New Orleans emphatically put that streak to a stop. Unable to get anything going because of its own rash of penalties — Atlanta was flagged 10 times for 91 yards while the Saints drew just three penalties — the Falcons struggled to get Freeman and backfield mate Tevin Coleman going. 

The Saints limited the pair to just 13 yards on eight carries in a shutout first half, and then rookie Marshon Lattimore broke the game open with the kind of play that will go down in history as a seminal moment in the rivalry's history.

As good as the defense had played in the first half, New Orleans led just 6-0 due to a slow start offensively, and Atlanta quarterback Matt Ryan took over with a chance to take the lead in the final 1:19 of the first half. Working over the middle, Ryan tried to force a pass in to Marvin Hall, who bobbled the ball up into the air and onto the butt of Lattimore.

Lattimore alertly grabbed the ball before it hit the turf for an interception — his fifth of the season, the most for any Saint since Darren Sharper had nine in 2009 — and instantly coined a moment, with media around the NFL instantly dubbing the play the "Butt Pick."

Brees capitalized by finding Ted Ginn Jr. behind the secondary for a 54-yard touchdown and a 13-0 halftime lead.  

New Orleans had been saving the play for just such an occasion. 

"That was a huge swing," Payton said. "We had seen something the last time we played them on film, wanted to get the look and it was perfect."

Two stops by the New Orleans defense with its back against the wall in the second half made sure Atlanta never got back into it. 

A missed Brees-Ginn connection to start the second half nearly let the Falcons back into the game. Atlanta linebacker Deion Jones, a New Orleans native, picked off a Ginn bobble and returned it to the Saints' 2-yard line. 

Saints nose tackle Tyeler Davison forced a Freeman fumble on Atlanta's second play, and Manti Te'o recovered to nullify the Jones interception. 

A 26-yard touchdown run by Mark Ingram pushed the lead to 20-3, and on the ensuing series, Atlanta made its last-ditch attempt, driving down to the 1 again, but Lattimore kept Jones out of the end zone on third down, and Hau'oli Kikaha stopped Freeman on fourth down to set off a celebration in New Orleans, although the Saints face another high-pressure situation in Tampa Bay next week. 

New Orleans likes it that way. Pressure brings out the best in this team.

"That's how you keep your edge," Brees said. "You want to keep your edge, and you want to keep ascending as you go into the playoffs, because those are the teams that really do something when they get there."

Follow Joel A. Erickson on Twitter, @JoelAErickson.