Carolina’s defense let the Saints claw back from a 20-3 deficit. (AP Photo/Bob Leverone)

With their coach brandishing a no-room-for-error mantra, the Carolina Panthers spent much of Thursday night seeing how wide they could stretch the margin for error.

A vexatious second-half showing nearly put the somber finishing touches on a much-anticipated season — a loss would’ve dropped the team’s chances of reaching the postseason to less than 1 percent.

Blowing leads late has become commonplace for Cam Newton and Co., so it was with no surprise that a 20-3 halftime lead over the New Orleans Saints rapidly evaporated. A rout became a slugfest. Newton’s fox tail-draped cleats ceased to become a talking point as he and the offense atrophied.

Ron Rivera watched his team — a group ranked last in the league in fourth-quarter point differential, turnovers and turnover differential — allow 17 points over the final 15 minutes for the second straight week. Only this time, the reigning Super Bowl runners-up escaped with a three-point victory, improving to 2-4 in games decided by five points or fewer (last season, Carolina went 5-0 in those games).

“It was a weird night,” tight end Greg Olsen said. “The only positive out of this entire thing is we won, which is a huge positive.’’

At 4-6, Carolina still occupies the basement of the division, two games behind the NFC South-leading Atlanta Falcons. The same roster that all 20 analysts and The Washington Post’s Neil Greenberg pegged as the cream of the division is vying to become the fifth team since 1990 to reach the playoffs after starting the season 3-6. Those are some long odds; even with Thursday’s win, Carolina’s chances of reaching the postseason are pegged at 11 percent, according to FiveThirtyEight.

It’ll be a difficult ladder to climb to get there.

The next two weeks yield matchups with two of top five teams in the league, both on the road. Four of the team’s six remaining opponents have winning records, three lead their respective divisions. Carolina, it’s worth noting, has yet to beat a team with a winning record this season.

While Mike Shula’s offense has noticeably regressed, the team’s more serious deterioration this year can be traced to the defensive side of the ball, particularly the ability to defend the pass. It manifested Thursday night, as Drew Brees carved up the Panthers in the second half.

Carolina entered this week ranked 19th against the pass in Football Outsiders DVOA metric, down 17 spots from a season ago. Last year’s defense allowed no more than 331 passing yards in a single game, while this year’s defense has allowed two different teams to throw for 460-plus. The peaks and valleys this season have been steep, if nothing else.

All of Carolina’s remaining opponents rank in the top 15 in pass offense DVOA and four rank in the top 10. Five of those teams rank in the top 15 in adjusted net yards per pass attempt, showing their respective starting quarterbacks provide significant value.

So while Thursday’s victory was impressive in that the Panthers held the league’s top offense to well below its season averages, it hasn’t yet shown that it can be anything remotely consistent. As safety Kurt Coleman put it: “It felt like we finally did what we were supposed to do.”

Also worth considering: Luke Kuechly, the team’s star linebacker who had played in 99.3 percent of snaps this season, left the game in the fourth quarter with what is being reported as a concussion. Should he be unable to play moving forward, it would be a crippling setback for a defense with little optimism already.

As for the offensive side of the ball, Newton is essentially a punching bag behind the lackluster Carolina offensive line. He’s been pressured at an above-average rate in every game since Week 6, and the line ranks in the bottom five in adjusted sack rate. That line has looming matchups with two of the four top defensive lines in the metric.

The route is clear: Carolina needs to win out to reach the postseason. Should the first 10 games of this season be any indication, it’ll be too tall an order for this team.

Josh Planos has been published at the Wall Street Journal, the Atlantic, the Guardian, the Pacific Standard and VICE, among other publications. He has been heard on CBS Sports Radio, Fox Sports Radio and ESPN Radio. Planos is a Digital Editor at KETV NewsWatch 7 and a freelance writer.