As recently as a few weeks ago, the mistake that the Washington Football Team’s defense made in the final seconds Monday might have doomed it. The miscue by safety Deshazor Everett, who replaced the injured Landon Collins and was playing his first defensive snaps of the season, might have negated what had otherwise been a stellar night.

Because when Everett didn’t carry Seattle Seahawks wide receiver Freddie Swain up the seam — exposing a huge hole in the cover-two zone, leading to an easy 32-yard touchdown — Washington’s momentum was gone, replaced by a thin, 17-15 lead with just 15 seconds left. The defense could have folded to late adversity, as it did twice in the first half of the season, but instead it responded with the resiliency Coach Ron Rivera has been waiting to see for months.

On the ensuing two-point attempt, cornerback Kendall Fuller had Seattle’s big wide receiver, DK Metcalf, in man-to-man coverage. Fuller shadowed Metcalf as he ran a crossing route from left to right, but in the middle of it, right underneath the goal posts, Fuller saw safety Kam Curl pick up Metcalf. Fuller disengaged and peeked into the backfield just as quarterback Russell Wilson rifled the ball right at him.

If Fuller hadn’t turned, if he hadn’t trusted Curl, Seattle almost certainly would have tied the score. Wilson zipped the ball high to Swain, just over linebacker Jamin Davis, for what looked like another Houdini-esque escape in a career full of them. But no. Fuller beat Swain for the jump ball, wresting it away to not only secure Washington’s third straight victory but also to illustrate the defense’s progress since the bye week that preceded the winning streak.

“That’s kind of what we were hoping for early on,” Rivera said of the defense’s resiliency. “Apparently we’re getting it now, so hopefully we can maintain it.”

In the past three weeks, even without the star edge rushers once expected to be the unit’s best players, the defense has looked much better. The uptick could be attributed to some combination of execution (coordinated rushes), scheme (jelling safety alignment) and circumstance (opposing quarterbacks off kilter, the offense’s clock-dominant approach keeping defenders fresh). Washington’s defense has only been on the field for 21 minutes 6 seconds per game during this three-game span, the lowest rate in the NFL.

Still, the improvement is stark. Washington has gone from one of the NFL’s worst defenses to average, according to the metric Expected Points Added, by dramatically reducing the rates at which it allows explosive plays and third-down conversions. In each of the past three games, the defense has allowed no more than 21 points — something it did only twice in its first eight games.

“We were mentally tough enough to get through the stretch where we weren’t playing as well, and now we’re starting to come out on the other side,” defensive tackle Jonathan Allen said. “The biggest thing for us is just consistency. We got to keep this going.”

In Rivera’s eyes, the key to a more resilient defense has been “playing together,” particularly on the defensive line and in the secondary. Since losing pass rushers Chase Young (torn ACL) and Montez Sweat (fractured jaw), whom Rivera criticized for not trusting their teammates, the coach has praised the line’s rush coordination, crediting it for securing the game-sealing sack last week at Carolina and preventing Wilson from scrambling as well as he did against Washington last season (six carries for 52 yards, compared with two for 16 Monday).

The two breakdowns Rivera cited Monday were on one of Wilson’s two runs (a 12-yard draw) and his final touchdown pass, when he stepped up into a spot where a rusher was supposed to be.

In the secondary, Rivera improved the cohesion by shifting Collins from strong safety to “Buffalo nickel,” a sub-package linebacker. Collins, a proud safety, opposes the switch — “I’m still not thrilled about it,” he said Monday — but has excelled at blitzing and being physical near the line of scrimmage. Collins also admitted that clearly defined roles with Curl at strong safety and Bobby McCain at free safety have helped communication, which players blamed for the big plays the unit allowed earlier in the season.

Washington’s secondary still has hiccups — Seattle hit a 55-yard pass because of a busted coverage late in the first quarter — but they happen infrequently enough as to not be critical. In this three-safety scheme, Washington can disguise coverages, which Curl cited as a main reason Tampa Bay Buccaneers quarterback Tom Brady threw two first-quarter interceptions against Washington in Week 10. The physicality Collins brings is also invaluable, as shown when he forced Seattle running back Alex Collins to fumble just before halftime.

The secondary has also improved because Rivera shifted Collins for Curl, one of the team’s youngest and most valuable defenders. Rivera said Curl had to play as much as possible, and the team often uses Curl in man-to-man against the opposing offense’s toughest matchup. Curl badly wanted to intercept Wilson, but he dropped the best chance he has had this year in the third quarter — though he made it up to himself by registering a sack and two tackles to keep players in bounds and the clock running during the final drive.

At the end of his news conference Monday, tight end Logan Thomas stopped and said he had something he wanted to share with the room.

“Y’all need to start respecting Kam Curl a little bit more, man,” Thomas said. “He’s a top-five safety in the league. Watch the film.”

All these tweaks have led, so far, to three wins. Certain moments provide hints that Washington could sustain better defense again, perhaps even level with the run to close out 2020, but it’s far from a guarantee. Rivera has said all year that that sort of assumption signifies the immaturity that until recently seemed to plague this unit.

“You don’t reward a fish for swimming,” Allen said of the winning streak. “We’re supposed to win football games. That’s what we get paid to do. So now we got to look at [the game film] with a critical eye and make sure we don’t get complacent. That’s the hardest thing: When you win, people start to relax a little bit and get ahead of themselves, and we can’t do that — because we haven’t arrived yet.”