ST. PAUL — Standing in the locker room moments after concluding one of the best regular seasons constructed by a team defense in recent memory, Vikings safety Harrison Smith was still not comfortable using the word “great” to describe his unit.

That 2017 Vikings defense led the NFL in yards allowed (275.9), points allowed (15.8) and third-down conversion defense (25.2%). The latter number was then the best in league history since the stat was first tracked in 1991, until it was bested this season by New England.

None of that mattered to Smith.

“I would not say we are great at this point,” Smith said at the time. “Hopefully there is a time (when we are), but not right now.”

Smith knew then what most understand now: Defensive greatness is earned in the postseason. The ones to be remembered forever deliver when it matters most.

In this century alone, it’s easy to recall the Ray Lewis-led Ravens that surrendered a total of 23 points in four playoff games on their way to winning Super Bowl XXXV, the Tampa Bay defense that shut down the Greatest Show on Turf in the 2002 NFC championshipe game before blitzing Oakland in the Super Bowl, and the 2013 Seahawks, who held Peyton Manning’s historically high-powered Broncos to eight points in Super Bowl XLVIII.

The 2017 NFL playoffs were going to be the Vikings’ signature moment.

Or so we thought.

It was quite the opposite. The Vikings were carved up by Nick Foles. A unit that looked uncrackable all season folded at the most inopportune time.

When Minnesota missed the playoffs in 2018, the window for greatness looked to be closing. It appeared to be sealed shut at points this season. This Vikings defense wasn’t bad — finishing 14th in yards allowed, fifth in points and 19th in third-down defense — but it was far from elite, and nowhere near good enough to carry a team through the postseason.

Or so we thought.

The unit that took the field last Sunday in New Orleans sure looked like the Vikings defense of old. Minnesota pressured Drew Brees, limited the Saints’ explosive options and forced timely turnovers, holding a Saints offense that averaged 36.2 points over its previous seven games to just 20.

Was that this dominant defense’s one-off swan song, or just the start of its long-overdue run to glory? We’ll have our answer Saturday. San Francisco’s defense is great. Minnesota’s will have to be greater.

“I think we’re gelling at the right time,” defensive end Everson Griffen said. “I feel like we have to be able to carry it over. Can we do it again this week? Can we play better? Because that’s what it’s going to take for us, to play better, to be able to win this game.”

Griffen had 1.5 sacks last week. Xavier Rhodes played a big role in slowing Saints all-world receiver Michael Thomas. The previously departed and only recently reunited Andrew Sendejo starred in his debut at slot corner.

There’s no guarantee any of those three will be back in purple next season.

By no means does this postseason signal the end of a strong Vikings defense. Smith, Danielle Hunter, Eric Kendricks, Anthony Harris and Anthony Barr are just a few stalwarts still in the prime of their careers.

But it is the last stand for this unit as currently constructed. Each of Sunday’s 11 defensive starters were also on the roster back in 2015. That’s incredible continuity for a league built on change. For this specific group as a whole, this is the last chance to cement itself as one of the best defenses to do it. Griffen admitted this week this unit looks for moments such as this to do just that.

They are few and far between.

“We are lucky that we’re back here in this position,” Harris said.

They’re set on taking advantage. Smith is likely still holding out hope that the time comes for this defense to be “great.” There’s no time like the present. Just play good football, defensive lineman Ifeadi Odenigbo said, and “the legacy takes care of itself.”

“Just go out there and play your ball. Go out there and line up. You know all the checks, all the motions, just go out there and be the best you can be on every play,” Griffen said. “I just want to be able to go out there and help this team win, just like every other guy on the defense.

“I feel like we have the team to do that.”