EAGAN, Minn. — Fans returned in full force in 2021, but the Vikings defense was never able to put together its ideal 11-piece ensemble.

Anthony Barr missed the first four games, plus later contests at Los Angeles and Detroit.

By the time Barr was able to work through his knee injury that hindered the start of the season, Michael Pierce, trying to play through an injury against Cleveland in Week 4, suffered a torn triceps that kept him out of the lineup until Week 13.

Other contributing factors to a substandard season included the following:

The loss of Danielle Hunter to a torn pectoral muscle in Week 8

Patrick Peterson suffering a hamstring injury late at Carolina in a game Minnesota should have put away much earlier

Harrison Smith being placed on the Reserve/COVID-19 list the morning of Minnesota's game at Baltimore; other players also landed on the Reserve/COVID-19 list down the back half of the season

Add it all up, and the Vikings ranked 30th in the NFL in yards allowed (383.6 per game) and 24th in points allowed per game (25.1). Minnesota also ranked between 25th and 29th in the following major categories:

Yards allowed per play: 5.66

Rushing yards allowed per game: 130.7

Rushing yards allowed per play: 4.68

Passing yards allowed per game: 252.9

Passing yards allowed per play: 6.87

It's hard to stack victories when a team is in the bottom quartile of those categories. For as many struggles as the group had, there were a few of positives.

Here's a deeper look at where the Vikings had successes in 2021 and two of their biggest priorities to fix going forward in 2022.

3 strong defensive stats in 2021:

1. Sacks aplenty

The Vikings finished the NFL's first 17-game season with 51 sacks, which tied the 1992 team (16 games) for the second-most recorded by Minnesota since sacks became an official stat in 1982.

Thanks, Bears, for allowing 10 of those in two games this season.

The record of 71 by the 1989 squad, which was fueled with 21 by Chris Doleman, 18 by Keith Millard, 11.5 by Al Noga and 9.0 by Henry Thomas.

D.J. Wonnum led Minnesota with 8.0 sacks this season, including 5.0 against Chicago.

For the first time in team history, the Vikings had five players each record 5.0 or more sacks.

Hunter finished with 6.0 in seven games. Everson Griffen recorded 5.0 in nine games before he needed to step away from the game for personal reasons.

Eric Kendricks and Armon Watts each tabbed career bests with 5.0 apiece after combining for 2.5 from 2019-20.

2. Pair of Pick-Sixes

The Vikings returned two interceptions for touchdowns in a season for the first time since 2016.

Two newcomers in 2021 — Nick Vigil (38 yards in Week 2 at Arizona) and Patrick Peterson (66 yards against Chicago in Week 18) — recorded the pick-sixes.

Minnesota totaled 256 return yards on 16 interceptions. That yardage total ranks fourth in team history. If not for Peterson's timely pick to extend his personal streak of seasons with at least one to all 11 seasons, the yardage total would rank 13th.

The record was set by the 2003 Vikings, who recorded — checks stats, double-checks and shakes head — 693 return yards on 28 interceptions.

3. Third-down rate was still stingy

A calling card of Mike Zimmer's tenure as head coach of the Minnesota Vikings will always be how tough opposing teams have had it when trying to convert third downs.

That again was the case in 2021, despite Minnesota's struggles in multiple other metrics.

Opponents converted 78 of 214 third downs (36.4 percent) this season, which ranked fourth in terms of stinginess in the NFL.

2 stats that need to improve in 2022:

1. Too generous inside the 2-minute warnings

As good as Minnesota remained in third-down defense, one situational area loomed large from the get-go and never really got fixed in 2021.

Cincinnati's two touchdowns inside the 2-minute warning to tie the game and build a 14-7 halftime lead weren't just the rise of Joe Burrow-to-Ja'Marr Chase (his first career touchdown was a 50-yarder with 35 seconds left in the first half). Instead, they were a sign of things to come for Minnesota's 2021 defense.

The Vikings allowed 93 points in the final two minutes before halftimes this season and an NFL-record (since the 1970 merger) 128 points inside all 2-minute warnings — which has a direct correlation to winning and losing football games.

According to Next Gen Stats, Minnesota's win probability went from 63 percent before Burrow completed a 2-yard touchdown pass to Tee Higgins to 57. It fell from there to 31 percent after Chase's score.

The following week at Arizona?

Minnesota allowed 10 and scored 3 in the final 1:33 of the first half, giving up a 77-yard touchdown pass and enabling Arizona to attempt a 62-yard field goal after driving 22 yards in 21 seconds.

The Vikings had a win probability of 59 percent before the long touchdown. It plummeted to 34 percent after the play. The number nudged up to 47 percent after a Greg Joseph field goal but fell to 26 percent after Matt Prater's kick.

2. Stop the run!

Opponents enjoyed repeated success when running the ball against the Vikings.

They averaged 4.7 yards per carry, a total that wasn't wildly skewed since the longest run allowed was 49 yards, and scored 15 times on the ground, compared to 10.

Foes finished with 2,222 rushing yards on 475 carries, which was 71 more yards on three more carries than the previous season.