Through five weeks of the 2022 season, the San Francisco 49ers have the best defense in the NFL.

The Niners have given up just 4.01 yards per play so far this year, the fewest in the league, while only they and the Dallas Cowboys have conceded fewer than 20 points in every game.

San Francisco's points totals allowed in 2022 – 19, 7, 11, 9, 15 – tell a tale of dominance, with Christian McCaffrey's rushing touchdown against the 49ers only the second the defense has conceded since giving up three in a rainstorm in their season opener to the Chicago Bears.

The 49ers' average of 12.2 points allowed is tied with that of the Buffalo Bills for the league's best. They have given up just 12 points in the first half, while no other team has conceded fewer than 35.

No defense has allowed fewer explosive plays of 10 yards or more than the 49ers (45), and San Francisco have forced a league-leading 44 negative plays from opposing offenses.

The Niners have given up four yards or more on only 42.9 per cent of first downs, the best ratio in the NFL, and they have allowed a conversion on just 30 per cent of the third-down attempts they have faced. The Tennessee Titans (27.1) and New Orleans Saints (29.9) are the only two defenses who can claim to have fared better in that regard.

Simply put, the 49ers' defense is dominating in every facet. The Niners do not give up explosive plays with regularity, excel at putting opponents behind the eight-ball by creating negative plays and limiting yardage on first down, and have little difficulty getting off the field on third down.

DeMeco Ryans' defense was already among the NFL's elite last year, but what has catapulted it to championship-calibre unit that has the potential to be the foundation of a deep San Francisco playoff run?

The perennial star of the show for the 49er defense is the front, which is teeming with depth at edge rusher and boasts several players who can thrive rushing from that position and from the interior.

No team has registered more quarterback sacks than San Francisco (21) and the 49ers' 91 pressures trail only the Cowboys (95) and Philadelphia Eagles (92).

The athleticism of linebacker Fred Warner, who displays extraordinary precision in zone coverage and can run with wide receivers downfield, is also critical to San Francisco's defensive success. 

Talanoa Hufanga's breakout second season has deservedly attracted substantial attention, the former fifth-round pick quickly becoming a walking highlight reel at the safety position, recording five tackles for loss, five pass breakups, one sack and two interceptions, including a game-clinching pick-six against the Los Angeles Rams in Week 4.

Hufanga has demanded attention with his enthralling hard-hitting and all-action brand of football, but just as crucial to the Niners and deserving of similar acclaim has been the play of cornerback Charvarius 'Mooney' Ward.

The 49ers' big-ticket free-agent acquisition in the offseason, San Francisco gave Ward a three-year, $40.5million contract with a view to him becoming the missing piece for a frequently maligned cornerback group.

Ward has unquestionably delivered to this point with his performances, combined with the emergence of Hufanga, helping transform the 49ers' secondary from an area of concern to a clear strength.

Arguably no 49er defender has done more to prevent big plays than Ward, who has been burnt – which is when a receiver wins his matchup on a play where he is targeted – on 10 of his 29 targets for a burn rate of 34.5 per cent. That is the fifth-best among corners targeted at least 20 times.

His big play rate, which tracks burns for 20 yards-plus or burns for touchdowns, of 18 per cent is 13th for his position. When wideouts have got in a position to catch the ball when going against his coverage, they have frequently seen it knocked away from them. Trevon Diggs (nine) is the sole defender to have produced more pass breakups than Ward's eight.

Through his strength in coverage and his proficiency for making plays on the ball, Ward has given the 49ers a lockdown corner they can rely on who offers a defense defined by its diversity even more flexibility.

Indeed, Ward's ability to consistently shut down wide receivers in man coverage is an asset to the Niners when they want to be more aggressive on defense, with San Francisco thriving through such an approach in the 24-9 beatdown of the Rams, in which they blitzed Matthew Stafford and an injury-hit Los Angeles offensive line on 30.4 per cent of dropbacks and were rewarded with seven sacks and 21 pressures.

Ward has also elevated the play of those around him in the cornerback room. Fellow starter Emmanuel Moseley has the third-best burn rate (31.8 per cent) among cornerbacks and nickel Deommodore Lenoir has given up a big play on 15 per cent of his targets, a rate bettered by just four corners.

The 49ers will now have to do some reshuffling in the secondary, however, after Moseley saw his season ended by a torn ACL suffered in Sunday's 37-15 rout of the Carolina Panthers.

Moseley's injury will mean either Lenoir shifting to the outside or one of Jason Verrett, Ambry Thomas or rookie Samuel Womack taking over at the spot across from Ward.

Without Moseley, the opposite side of the field to Ward may be viewed as a potential vulnerability in a defense that has presented none this campaign.

But San Francisco's defensive backfield is better equipped to deal with a serious injury than it was a year ago. The 49ers' misfortune may have robbed them of the top-tier starting cornerback duo Ward and Moseley looked like becoming, but their astute investment in the former has ensured the Niners' secondary is now one opposing offenses have significantly less hope of succeeding against.