NEW ORLEANS — Whether it was the weirdest interception of Marshon Lattimore’s football life or a ball-dislodging hit by Tyeler Davison near the goal line, the New Orleans Saints’ defense poetically tipped the scales in a long-awaited playoff-clinching victory Sunday.

Shoddy defense was widely seen as the reason the Saints missed the playoffs for three years. Those days are over.

Lattimore corralled a momentum-turning interception off his backside, and New Orleans made two defensive stands from inside its 2 as it clinched its first postseason berth since 2013 with a 23-13 victory against the Atlanta Falcons.

“We want the team to win because of the defense, not in spite of the defense, and I feel we’ve all kind of hung our hat on that,” Davison said. “We saw it in our mind and we turned it into real life, man, and it feels amazing. It feels just as you thought it would when you pictured it 100 times.”

Ted Ginn caught a 54-yard pass for a touchdown, which came a few plays after Lattimore’s interception and shortly before halftime. Mark Ingram used a sharp cutback to break loose for a 26-yard touchdown for New Orleans (11-4), which kept its tenuous hold on first place in the NFC South heading into the final week of the season.

While the loss eliminated the Falcons (9-6) from the NFC South race, they can clinch a wild-card berth by beating Carolina in the regular-season finale.

The Falcons entered the game with a second straight division title within reach but needed to beat the Saints. They squandered chances spectacularly.

Atlanta trailed 6-0 when Lattimore’s interception of Matt Ryan set the Saints up to increase their lead.

Early in the third quarter, Deion Jones of Atlanta intercepted a pass that deflected off Ginn and returned it 41 yards to the New Orleans 2. But Devonta Freeman fumbled on a hit by Davison two plays later and linebacker Manti Te’o recovered.

“That was my fault,” Freeman said. “No matter what play is called, you’ve got to get in the end zone and score, and I’ve got to protect the ball. I’ve got to do better at that. I’m going to do whatever it takes to fix it.”

Early in the fourth, Freeman was stopped on fourth-and-goal from the 1, preserving a 20-3 Saints lead.