The Cardinals defense was among the league's worst in 2019, allowing the fifth-most points and highest number of yards in the NFL.
Amid a slew of injuries, Arizona's defense improved substantially in 2020, with progression from the team's younger pieces like safety Budda Baker, linebacker Haason Reddick and cornerback Byron Murphy Jr.
The unit had its share of down moments, but down the stretch, it performed well enough to keep the team competitive.
1. Week 14 @ New York Giants (26-7)
This was a week in which the defense won the game.
Arizona allowed its fewest points in a week since 2017, and picked up three takeaways and a season-high eight sacks while at it. Reddick alone earned five sacks, a franchise record, and three forced fumbles.
The Giants had nearly as many possessions end in turnovers or from a three-and-out as they had first downs (10-9).
The Cardinals allowed their fewest yards of the season, along with their second-fewest rushing and passing yards.
Reddick won the ensuing NFC Defensive Player of the Week award.
2. Week 12 @ New England Patriots (17-20)
This game resulted in loss, but the defense was the least of Arizona's troubles. The offense blew a chance to score at the goal line before halftime, then produced just seven points in the second half.
Special teams played its worst game of the season, as both Patriots touchdown drives started in Cardinals territory after long returns.
The defense, meanwhile, allowed a season-low 69 passing yards and its second-lowest total yards with 179. They had two interceptions, one of which led to a touchdown, the other to a field-goal try (missed).
In defensive DVOA (Defense-adjusted Value Over Average), this was their second-best performance behind the Giants game.
3. Week 17 @ Los Angeles Rams (7-18)
In a win-or-go-home game, the Cardinals defense did not concede a touchdown. The season finale was the team's only week without allowing its opponent into the end zone in 2020.
Of the Rams' 18 points, just three field goals were produced by their offense, as a safety and an interception return accounted for the other nine.
An interception by Arizona linebacker Jordan Hicks on the first Rams offensive play of the game set up his team's sole touchdown.
The Cardinals defense also faced the challenge of being on the field for over 37 minutes, as an early injury to their quarterback, Kyler Murray, set up up a rough day for the offense.
4. Week 6 @ Dallas Cowboys (38-10)
This could be called the "Budda Baker game".
The eventual All-Pro safety picked up his first career interception after diving in front of a pass in the fourth quarter. He also sacked Dallas quarterback Andy Dalton and stripped halfback Ezekiel Elliot for a takeaway.
He won the NFC Defensive Player of the Week award.
As a team, the Cardinals forced four turnovers, a season high that jump-started their offense. After three punts, Arizona scored on back-to-back drives, both off takeaways.
Dallas' 10 points tied for the second-fewest Arizona allowed in a game this year.
5. Week 2 vs. Washington Football Team (30-15)
Midway through the third quarter, the Cardinals were pitching a shutout.
Washington quarterback Dwayne Haskins had only 94 passing yards, and his team's possessions started with two punts, a fumble and then four more punts.
Arizona also had four sacks and seven tackles for loss, and the game was seemingly settled at halftime when the score read 20-0.
Washington came back with a better fourth quarter, scoring 12 points to cut the deficit to two possessions, but it never got in striking distance of stealing the win.