How do Super Bowl teams' defenses stack up?

They say defense wins championships.

That axiom may not apply to the NFL anymore. Both Super Bowl participants had sub-par defenses during the regular season. The LA Rams ranked 19th in total yards allowed. The New England Patriots ranked 21st.

But both teams made the Super Bowl largely because they played excellent defense during the conference championship round two weeks ago. The Patriots held the Kansas City Chiefs’ No. 1-ranked offense to just 290 net yards, and the Rams held the New Orleans Saints’ No. 8-ranked offense to the exact same amount.

The winner of the Super Bowl could be the team that plays better defense Sunday.

To learn more about each defense and what each might plan to do in the Super Bowl, here are insights from someone who has coached defense in the NFL. He requested anonymity.

Sizing up the Patriots defense

“What you’ve seen on tape is not what you’re going to get,” the defensive coach said. “The Patriots are very game-plan specific. They’re so reliant on veterans who are smart, because it’s hard to be great at their scheme. When you change it every week, you really need smart football players.”

In other words, some NFL defensive coordinators present one or two new wrinkles every game, while Patriots head coach Bill Belichick presents nothing but new wrinkles.

“Belichick will mess with all your offensive rules,” the coach explained. “The Patriots defense is going to get you schematically — that’s why sometimes their defense is hit or miss.”

If Belichick’s game plan works in the Super Bowl, the Patriots defense will play well. If his game plan doesn’t work in the Super Bowl, the Patriots defense will get shredded because it lacks top-end talent. It’s scheme dependent.

“The Patriots do a really good job of playing complementary football,” said the coach. “They play just good enough on defense to complement their potent offense. That’s what they do. And they keep it cheap on defense. They get castoffs.”

One castoff is linebacker Kyle Van Noy. The Detroit Lions took him in the second round of the 2014 draft.

In three seasons with the Lions, Van Noy started only seven games. Midway through the 2016 season, the Lions gave up on Van Noy and traded him plus their seventh-round pick in 2017 to the Patriots in exchange for New England’s seventh-round pick in 2017.

A modest pick swap. Now, Van Noy is the Patriots’ starting middle linebacker.

“He’s a really smart football player,” the coach said. “In New England, he’s not doing anything special, but he’s functional. He gets the job done. They’re able to maximize his athletic talent, which they’ve been able to do with a bunch of castoffs over and over again because the Patriots can field a functional defense while still paying the quarterback and the offensive players.”

Meaning the Patriots defense strives merely for functionality, and it is cost-effective for the organization.

“When Tom Brady was first playing, they were loaded on defense,” the coach said. “They had Willie McGinest, Lawyer Milloy, Ty Law — they had everybody. Now, it’s like, ‘Damn, why’d they trade (edge rusher) Chandler Jones?’ It’s because Brady is making all kinds of money. I imagine if Brady ever retires, you’re going to see a big shift in the way the Patriots allocate their spending.”

Sizing up the Rams defense

“Wade Phillips is more simplistic than Belichick,” the coach explained.

Phillips is the Rams’ defensive coordinator.

“Wade’s system hasn’t changed at all,” the coach continued. “He has adapted a little bit here and there, but for the most part, he has a system that has stood the test of time. The Rams are going to do the same things over and over again on defense, and they’re going to get really good at those things and play very, very fast.”

The 49ers defense has the same philosophy — keep everything simple and play fast — although the 49ers mostly use zone coverage. Phillips prefers man-to-man coverage.

“You’re not going to see much variation from week to week with Wade,” the coach said. “What he did in training camp and OTAs is what you’re going to see throughout the season. You might get a wrinkle here and there, but he calls the same three things over and over.

“His system is reliant on having really good pass rushers and corners. Those positions are premiums when you play a lot of man coverage. They’ve got to have great guys in the back end. They’ve got to be able to rush the passer, or they’ll end up in trouble, because man coverage is the easiest way to give up explosive passes if the rush and coverage isn’t good.”

That’s why during the offseason the Rams signed cornerback Aqib Talib, cornerback Marcus Peters and defensive tackle Ndamukong Suh, then traded for defensive end Dante Fowler at the trade deadline, to augment their pass rush and man coverage.

“The Rams are not reliant on linebackers,” the coach said. “Their free safety, LaMarcus Joyner, is pretty good. And obviously, (defensive tackle) Aaron Donald has wreaked havoc. They have a very talented group, and they’ve turned it up for the playoffs.”

How the Patriots will defend the Rams offense

Belichick always wants to take away what the opposing offense does best. What does the Rams offense do best?

“People don’t realize it,” the coach said, “but the Rams run the crap out of the football. I could see Belichick trying to do what the Chicago Bears did to the Rams offense earlier this season.”

In Week 14, the Bears limited the Rams to just 54 rushing yards — by far the Rams’ worst offensive performance of the season. They lost 15-6.

“The Patriots will put a premium on edge-setting and clogging the middle with their big guys,” explained the coach. “I imagine the Patriots will play a 3-4 defense, so the Rams’ run game and play-action rollout passing game won’t work.

“Then, I imagine Belichick will dare (Rams quarterback) Jared Goff to beat him. And by dare, I’m talking drop-back passes, not play action. So much of the Rams offense is predicated on play fakes and rollouts. Once you get Goff dropping back, the game changes. Now, the Patriots will double-cover Brandin Cooks, Goff’s favorite receiver, and force Goff to go through his progressions and make tough throws.”

How the Rams will defend the Patriots offense

“This one is very interesting,” the coach said. “If the Rams try to play man coverage, they will get rocked. And that’s what Wade likes to play.”

Two weeks ago, the Chiefs defense played lots of man coverage against the Patriots in the AFC championship game and got rocked. Gave up 37 points, then fired defensive coordinator Bob Sutton two days later.

But Phillips is better than Sutton.

“Wade has done an unbelievable job holding Tom Brady under his season averages,” the coach said. “There’s a lot of history there.”

Brady and Phillips have faced each other nine times. In those nine games, Brady’s quarterback rating was 91.2 — slightly below his career rating of 97.6. Phillips did well, although Brady’s record against him is 6-3.

“I have never really gotten a chance to study what Wade has done to Tom in the past,” the coach said. “It’s going to be a cool little offseason study I have planned. But in this matchup, I don’t see Wade varying much from who he is.”

Picking a winner

The Patriots will make their ninth appearance in the Super Bowl. These Sean McVay Rams will make their first.

“The Patriots definitely will get it done,” the coach said.

Nothing complicated about that.