NEW ORLEANS — Statistically, the beleaguered New Orleans Saints defense couldn’t possibly slip any lower in the NFL rankings going into Monday night’s game with the Philadelphia Eagles.

Then, they went out and gave up 131 total yards in the first quarter and looked for all the world like they would be run out of the Mercedes-Benz Superdome by halftime by quarterback Michael Vick and the Eagles.

But the most important number that came out of the first quarter was zero: the number of points the Saints allowed in holding an opponent scoreless in the opening period for the first time this season.

At the same time, they came up with three big plays — the biggest a 99-yard interception return by cornerback Patrick Robinson — that kept the Eagles in check and provided the early impetus for a much-needed 28-13 win.

Even though the defense eventually allowed 447 yards, the Saints rattled Vick throughout the night. They got to him for seven sacks, the most he has had since joining the Eagles in 2009, and had two takeaways in delighting a crowd of 73,099.

“I was proud of our football team to be able to improve on some things that we really worked on and emphasized this week,” Saints interim coach Joe Vitt said. “Make no mistake, we have a long way to go. But the red zone defense, the pressure … were very encouraging.”

The seven sacks were a season-high, while the points given up were a season-low — 11 fewer than the Saints (3-5) allowed in a 31-24 victory over the San Diego Chargers on Oct. 7.

What’s more, the Eagles (3-5) had a first-and-goal four times during the game and came away with just six points on field goals of 22 and 37 yards by Alex Henery.

Sacks by defensive ends Martez Wilson and Cameron Jordan, a crushing 22-yarder, on the first series set the tone and forced the Eagles to punt from their side of midfield after they had quickly marched to the Saints’ 27.

The sack for Jordan, who had three sacks going into the game, was the first of three on the night. Defensive end Will Smith also had two — matching his season total as well — while Wilson and defensive tackle Brodrick Bunkley had one sack each.

“We saw that the Eagles had given up a lot of sacks and that Vick had been hit a lot,” said Jordan, the team’s top draft pick in 2011. “So I was glad the defensive line got together this week. It was all about the defensive line getting after him.”

It tied the most sacks against Vick in his career. The only other time he had been dropped seven times in a game was against the New York Giants in 2006 when he was with the Atlanta Falcons.

On their second possession, the Eagles mounted another drive and got to the Saints’ 5 on a 40-yard run by Bryce Brown.

But two plays later, Vick’s pass to tight end Brent Celek glanced off his hands and into the arms of Robinson.

Robinson, a three-year veteran, returned the interception 99 yards down the sideline in front of the Eagles’ bench, giving the Saints a 7-0 lead with 2:36 left in the first quarter.

“That was a big play … that was a 14-point swing, the seven we got and the seven they didn’t,” Vitt said.

Robinson’s interception return tied the franchise record set by free safety Darren Sharper in a 24-10 win over the New York Jets on Oct. 4, 2009.

After that, the Saints’ offense got into the act as running back Chris Ivory, who saw his first action of the season in place of an injured Darren Sproles, had a 22-yard touchdown run after Henery’s first field goal to push the Saints’ lead to 14-3 with 8:33 left in the second quarter.

Quarterback Drew Brees, who was 21-of-27 for 239 yards in leading the Saints to 371 total yards, then threw a 1-yard touchdown pass to wide receiver Marques Colston with 1:13 left in the second quarter to give the Saints a commanding 21-3 halftime lead.

Then, when the Eagles struck back with 10 quick points in the third quarter on a 77-yard scoring pass from Vick to DeSean Jackson and Henery’s second field goal to narrow the gap to 21-13, the Saints responded.

Brees cranked up a 70-yard drive and capped it with a 6-yard touchdown pass to tight end Jimmy Graham with 1:20 remaining in the third quarter, setting the stage for the defense to do the rest.

Even then, the Saints defense stiffened when the Eagles drove deep into their territory on their final two possessions.

But after reaching the Saints’ 5, Celek fumbled the ball away when hit by linebacker Curtis Lofton, and backup safety Isa Abdul-Quddus fell on the ball to end that threat.

Then, the Eagles reached the Saints’ 15 and had a first-and-10 only to be turned away again when Vick, who was 22-of-41 for 272 yards, spiked the ball to stop the clock had three more incompletions to finish off a dreadful night.

“Tonight was fun,” Brees said. “When you’re moving the ball offensively, when you’re scoring points, when you’re rallying around your defense when they make a big play.

“That interception (by Robinson), that’s a huge, huge play in the game, especially at the start of the game when you’re trying to build some momentum and get rolling. That’s a great way to do it.”