As the clock wound down on the Ravens’ first loss in six weeks, quarterback Lamar Jackson peeled off his helmet and sent it thundering toward the grass of Huntington Bank Field in Cleveland.

The reigning and two-time NFL Most Valuable Player had seemingly done enough: 289 yards through the air, a pair of passing touchdowns and the orchestration of a 91-yard scoring drive to take the lead in the final three minutes. But his defense coughed up that lead. When Jackson’s last-ditch heave to the end zone hit the ground, so went his helmet.

Last year’s Ravens defense was historically good. A coordinator change and a few notable departures left the bones of the group intact. What their five-game winning streak concealed was plopped in an interrogation chair under fluorescent light after that Cleveland loss; they’ve had an historic regression.

Former defensive coordinator Mike Macdonald had the 2023 Ravens atop the league in points allowed, sacks and takeaways. They’re now 26th in points allowed and have given up just one fewer passing touchdown through eight weeks than they did all of last year. This autumnal unraveling took them from sixth in average passing yards allowed to 32nd out of 32 teams.

For those more inclined to advanced metrics, they were second in expected points added per play (-0.121) — which calculates performance on a play-by-play basis — last year and have since fallen to 26th (0.084). Similarly, they were first in defensive DVOA (-23.3%), measuring how well a team performs compared with the league average. Closing in on the halfway mark of this season, Baltimore is 18th (2.7%).

Context is crucial.

A trio of starters (Jadeveon Clowney, Patrick Queen and Geno Stone) all signed elsewhere. And perhaps most significantly, Macdonald took the head coaching job in Seattle, succeeded by first-year coordinator Zach Orr.

This year’s group has been exceptional in run defense, ranking first in the NFL. But the secondary has dropped a league-most eight interceptions, and they’ve given up 21 completions of at least 25 yards, more than any other team.

The Ravens hit a new low. Whether the optimism emanating from the locker room in Owings Mills will lead to a turnaround remains to be seen.

“Even though you’re putting in the work, everything doesn’t come as fast as you may want it to. All you can do is continue to grind and continue to chase perfection and continue to work,” Orr said. “We know that attention to detail is going to pay off.”

Three former Ravens teams have endured similar regressions. None were quite as dramatic as this.

The 2000 defense is considered one of the greatest ever. They conceded only 10.3 points per game — better than any team since at least 1978, when the NFL expanded to 16 regular-season games. It took two years for that group to lose its footing. They dropped off a smidge in 2001 to the fourth-fewest points allowed and the second-fewest yards. By 2002, they were a bottom-half group in both categories, stifled by linebacker Ray Lewis’ season-ending injury.

Lewis once said that if there’s a year that keeps him up at night most in retirement, it’s 2006. The Ravens were sent home in the divisional round despite leading the NFL in just about every defensive category. First in yards against, first in defensive DVOA, first in opponent third-down conversion percentage and first in points allowed (12.6), a mark no team has matched since.

One year later, they were 22nd in points allowed and 20th in passing yards against.

Then there was 2011. Baltimore was first in pass defense DVOA and second in rush defense DVOA before its season sailed wide left with a missed field goal attempt by Billy Cundiff in the AFC championship game. That offseason, Dean Pees — who is currently a consultant for Orr — was hired as defensive coordinator. The group’s league-wide rankings slipped to 13th in pass defense and 25th in rush defense. They still won the Super Bowl.

If there is a team to have free fallen further than these Ravens, it’s the 2001 Tennessee Titans. In 2000, they were first in defensive DVOA and yards allowed (both beating out Baltimore). The Titans then plummeted to 30th in defensive DVOA the following year because, as ESPN’s Sean McCormick later wrote, they “couldn’t cover receivers — any receivers.”

For the Ravens, the checklist to fix their pass defense, according to safety Kyle Hamilton, is “execution, winning one-on-ones — it really comes down to that at the end of the day — and guys just going out there and being confident in what they do and having the belief that we’re going to go get it done.”

Baltimore doesn’t have to dig much through the history books to find another example of a team whose defense struggled mightily to keep up with its league-best offense. The 2018 Chiefs were, at this point in the season, the best offense in football while on pace to join the 2012 Saints as the only team in NFL history to give up more than 7,000 yards (Baltimore is on pace for 6,141).

Those Saints experienced their own defensive collapse. They won the Super Bowl in 2010 with the fourth-best defense in the league. A year later, they were 24th, ranked outside the top 10 in every major defensive category — largely because of injuries and suspensions.

Quantifying and comparing defensive drop-offs isn’t an exact science. Each looks and feels unique. The salary cap era makes it harder to keep potent groups in tact. Different stats tell a different story.

Orr’s mixing and matching of man and zone schemes with a healthy influx of blitz packages has been exceptional against the run. Yet, an excess of easy completions over the middle and explosive plays puts more pressure on the offense to avoid situations in which the franchise quarterback is left spiking his helmet.

“There is a lot of outside noise, and there is a lot of adversity, as well, but you can’t get rattled,” linebacker Roquan Smith told a throng of reporters hovering over his locker. “We’re going to be perfectly fine. We’ll look back at this interview pretty soon, and you’ll be like, ‘You were right.’ ”