The New Orleans Saints spent the past month looking like a team that had turned the corner, had buried a disappointing start and had developed an identity for a remade roster that was starting to figure out how all the pieces fit.

And the Saints had plenty of opportunities to cement their midseason resurgence Sunday in the Mercedes-Benz Superdome against a Tennessee Titans team that spent the week in the turmoil of a coaching change.

Old issues surfaced instead, allowing Titans rookie quarterback Marcus Mariota to match Drew Brees blow for blow, then keep the ball out of Brees’ hands by tossing a game-winning touchdown pass to Anthony Fasano on the first drive of overtime for a 34-28 win that snapped the Saints’ three-game winning streak and left New Orleans trying to fight back to .500 again.

“It’s a loss. There’s not a lot of wiggle room when you start off the way we started,” Saints coach Sean Payton said. “To get that consistency we’re looking for, we’re going to have to be better in a lot of areas, or else it’s going to be kind of a streaky, here-and-there type deal.”

New Orleans (4-5) should have put the Titans away early.

Playing behind the continued hot hand of Drew Brees, who followed up his record-setting performance against the New York Giants by completing 28 of 39 passes for 387 yards, three touchdowns and one interception, the Saints leaped to a 14-3 lead, the only Titans score coming after field position was gifted to Tennessee by Marcus Murphy’s early fumble.

Then a defense that has been plagued by the big play all season gave up another in bizarre fashion. Harassed and hurried after three-and-outs on his first three drives, Mariota flung a desperation heave on third down that looked like a sure interception for Saints cornerback Keenan Lewis. Free safety Jairus Byrd, drifting over to make the play himself, collided with Lewis, and the ball bounced into the hands of Titans tight end Delanie Walker, who raced away with a 61-yard touchdown.

“This isn’t a ‘one guy calls the other one off’ type of situation,” Byrd said. “You’re just going for the ball. It was a pop fly. You can’t call it; you just go for it.”

Big plays like the one Walker made have erased stretches of improved play from the defense all season, and the touchdown seemed to galvanize the Tennessee offense. Mariota, who was playing his first game in three weeks after missing two with a sprained knee ligament, responded to Brees’ third straight touchdown drive with one of his own, sparked by a 38-yard run by Antonio Andrews.

Andrews averaged 2.8 yards per carry on his other 18 carries.

“Everybody in this league is good and everybody can play, but you’ve just got to be able to execute and be consistent,” Saints linebacker Kasim Edebali said. “You can’t have one good series and one not. ... We have to become more consistent.”

Mariota, who matched Brees by completing 28 of 39 throws for 371 yards and four touchdowns, also had the benefit of working in one of the cleanest pockets he has seen all season. Tennessee’s line had given up four sacks per game entering Sunday’s tilt; an improved Saints pass rush, even forced to play without the services of rookie linebacker Hau’oli Kikaha, was expected to take advantage.

But the Saints looked more like the unit that came away with just seven sacks in its first five games.

“We knew he was a fast guy, and we knew we had to keep him in the pocket, but they did a good job with their play-action and their bootlegs, and they were able to separate him from us and give him a little more time to throw,” Edebali said. “We’ve got to do a better job.”

A rebirth of old issues hamstrung the Saints offense, too. New Orleans picked up just 59 yards on the ground, repeatedly forcing the Saints into obvious passing situations.

And that allowed a dangerous Titans front four to tee off, sacking Brees four times, including a key sack on the Saints’ final drive in regulation that made Kai Forbath’s potential game-winner a longer kick.

Facing a Saints offense that had to throw, Tennessee dialed up a few more blitzes, and the final sack came when a Titans player was missed by the protection and came free.

“(If) you’re not running the ball, you’re going to get a lot of pressure,” Saints right tackle Zach Strief said. “We put ourselves in that situation, and it’s tough. Teams can get exotic, and hats off to them; I think they turned it up at the end.”

The final mistake came from a special-teams unit that has been largely solid, save for the field-goal process. After a questionable decision by Tennessee interim coach Mike Mularkey to try a 55-yard field goal gifted Brees good field position, the Saints got a 46-yard field-goal attempt for Kai Forbath, but the kick was partially blocked, forcing overtime. Mariota took the ball and never looked back.

Now the Saints have to find a way to fix those issues and get back to what produced the three-game winning streak that ended Sunday.

“I know we can run the ball better,” Brees said. “I know we can stop the run better. All of those things that mean winning in football, we didn’t do enough of today.”