Patriots defense is hitting its stride

The Patriots’ Chris Long (right) celebrates with teammate Rob Ninkovich (left) after a Ninkovich sack against the Ravens. jim Davis/globe staff

Bill Belichick likes to say that the first four games of the regular season are almost like an extension of the preseason, with the coaching staff needing the early games to figure out how to best use its personnel.

After Monday night’s impressive 30-23 win over the Ravens, the Patriots’ defense is finally hitting its stride. All it took was a “midseason preseason” stretch of the schedule, and a total reevaluation of the Patriots’ defense.

Belichick hit the reset button on the defense during the Bye week, trading away Jamie Collins and starting fresh with new personnel such as Shea McClellin, Kyle Van Noy, and Eric Rowe.

The first game against the Seahawks was atrocious. But they played three offensively-challenged teams in a row — the 49ers, Jets, and Rams — and used this easy stretch of games to evaluate their personnel and figure out the best ways to use their new guys.

They have settled into a nice rotation at defensive end, with Chris Long, Trey Flowers, Jabaal Sheard, and Rob Ninkovich each playing 35-45 snaps per game. Van Noy has 14 tackles, a sack, an interception, and two passes batted down as a hybrid pass rusher/linebacker. McClellin and Van Noy also play about 35 snaps per game, sending undersized and struggling rookie Elandon Roberts back to the bench.

And Matt Patricia is picking his spots better.

The Patriots didn’t blitz Joe Flacco often on Monday night, but a six-man blitz on third and 4 resulted in a huge sack for Ninkovich on third down late in the game. Patricia has also been getting creative, unleashing Donta Hightower, Logan Ryan, and Patrick Chung on blitzes the last few weeks.

Allowing only 3 points to the Rams last week was nice, but Monday’s performance was the real test. The Ravens have a big-game quarterback, speedy veteran receivers, and a smart head coach.

The Patriots’ defense responded with perhaps its best — or at least most clutch — performance of the season. The Ravens’ only touchdowns came off of two turnovers deep in Patriots’ territory. The Patriots sacked Flacco twice, forced a safety, and limited a hot Ravens team to 348 yards and three field goals.

It took a while, but the Patriots just may have figured out their defensive formula as they prepare for the playoffs.

Other observations after watching the tape:

When the Patriots had the ball . . .

■  Ravens defensive coordinator Dean Pees mostly played it safe against Tom Brady, as most teams have been doing this year. Brady dropped back to pass 40 times, and Pees only blitzed on eight snaps.

Pees was conservative in between the 20s, though the Ravens did occasionally overload one side of the offensive line, causing Brady to rush his throw a bit.

But Pees got aggressive once the Patriots got in the Red Zone. And Brady capitalized.

Against a five-man blitz, Brady was 4 of 5 for 45 yards and a 19-yard touchdown to Martellus Bennett, and was sacked by Eric Weddle. I usually don’t like the deep fade pass on third down, but Bennett had 6 inches on linebacker Zach Orr and came down with the jump ball.

The Ravens blitzed six just one time, and it resulted in a defensive holding penalty. And on consecutive plays in the second quarter, the Ravens blitzed seven when the Patriots got inside the 10-yard line. The first pass was batted down by Terrell Suggs.

The next play was a touchdown to Malcolm Mitchell, who beat the single coverage.

■  The Patriots’ run game against the Ravens’ No. 1 run defense was impressive enough. But the reason to keep at it, even when six of LeGarrette Blount’s runs are stuffed for 2 yards or fewer, is to keep the defense honest.

Brady shredded the Ravens with his playaction passes, completing 6 of 6 for 170 yards and a touchdown, as the Ravens linebackers fell for it every time. Included in that was a 28-yard flea-flicker to Chris Hogan, two wide-open catches for Bennett down the seams for 45 yards, and Hogan’s 79-yard touchdown, in which Eric Weddle bit just enough for Hogan to blow past him.

■  In fact, the Patriots’ other big play also resulted in the safety biting down and missing the deep assignment.

James White was lined up against linebacker CJ Mosley on the outside, with Lardarius Webb in single-high safety coverage.

But Webb bit on the underneath route to Julian Edelman, leaving White with all kinds of real estate to scamper for 61 yards.

■  Brady’s interception came against a four-man rush. The Patriots didn’t identify it correctly, as seven players stayed in to block, and Brady only had three receivers against seven defensive backs. Hogan slipped while making his cut, Edelman and Mitchell were covered, and Brady made an ill-advised throw instead of just taking the sack.

■  But credit Brady for taking advantage of the Ravens’ shaky cornerbacks. They gave the Patriots plenty of space at the line of scrimmage, and Brady once again chewed them up underneath with quick hitches and quick outs. Brady’s most underrated throw of the night was a 16-yarder to Edelman on the sideline that was dropped in the bucket.

■  Great day from the offensive line, keeping Brady clean and opening some decent holes for Blount. The Patriots rushed for 22 yards on consecutive runs in the second quarter, first running an off-tackle play to the left with a pulling Shaq Mason, then flipping it to the right side on the next play with a pulling Joe Thuney. Mason and Thuney were excellent in the run game, and Nate Solder, James Develin, and Bennett had great seals, as well.

Solder did a great job 1-on-1 on Suggs all game, holding him to half a tackle and no QB hits. Thuney did struggle a bit in pass protection, allowing a pressure and a QB hit to Timmy Jernigan. Marcus Cannon was up and down against Elvis Dumervil, as well.

■  Interesting to see Hogan (57) and Mitchell (54) play more snaps than Edelman (47). But Edelman was still the security blanket, receiving a whopping 15 targets, or one every three snaps. Dion Lewis (17 snaps) took a clear back seat to White (29), while Cameron Fleming was used as a sixth offensive lineman on 18 of 68 snaps.

When the Ravens had the ball . . .

■  The Patriots played it safe most of the day. Here is the breakdown:

3-man rush: 10 of 16, 97 yards, interception, 0 for 4 on third down.

Regular 4-man rush: 16 of 21, 116 yards, touchdown, sack.

Zone-4 blitz: 8 for 9, 31 yards, one first down.

Blitz-5: 3 for 5, 80 yards, touchdown.

Blitz-6: Ninkovich sack.

Hanging back with a three-man rush produced a lot of completions, but for minimal gain. The Patriots did a great job of swarming to the football on dump-offs to running backs and underneath throws to receivers, and for the most part made some nice open-field tackles ( Chung stood out in this area).

■  The Patriots were more than happy to let Flacco sit in the pocket and take his chances. And Flacco complied. He made a baffling decision to throw deep to Mike Wallace with Devin McCourty and Chung both back in deep safety, and McCourty made a great play on the ball for an interception. The throw was reminiscent of Flacco at the end of the playoff game two years ago, when he needlessly chucked the ball into the end zone for an interception by Duron Harmon.

And Flacco was simply incapable of piecing together long drives. Of the Ravens’ 14 true drives, only two went more than 50 yards and only one lasted 10 plays. Both occurred in the fourth quarter.

■  The blitz was more boom-or-bust. A Hightower blitz forced Flacco to throw away, and Ninkovich’s huge third-down sack came on a six blitz. The Patriots also blitzed on Kenneth Dixon’s 8-yard touchdown (the Patriots had pre-snap confusion and either Devin McCourty or Hightower blew the assignment). Breshad Perriman also made a 47-yard catch on a Malcolm Butler corner blitz, and Steve Smith made a 25-yard catch to convert a third down.

■  The 40-yard catch by Ravens fullback Kyle Juszczyk came on a three-man rush, in which Van Noy appeared to be very late in getting over into coverage. Great hustle by Logan Ryan and Cyrus Jones to tackle Juszczyk from behind.

■  Van Noy had a nice tipped pass over the middle, in which he goaded Flacco into a quick slant but then dropped off into coverage, and a run stuff with Hightower and Alan Branch. But Van Noy seemed a step slow on a few assignments, as well.

■  Malcom Brown had a real active game, notching a couple of internal pressures in addition to the safety.

Ravens right guard Vlad Ducasse missed his assignment, blocking Roberts and leaving Brown 1-on-1 with the fullback, which is a total mismatch.

■  Ryan gives up a lot of catches, and we counted at least three third-down conversions in which he was in coverage — a couple to Mike Wallace and one to Kamar Aiken. But Ryan also deserves credit for being a sure tackler and very rarely allowing yards after the catch. He allows receptions, but at least makes receivers fight for them.

■  Cyrus Jones did OK in coverage, though he was burned by Perriman for the 47-yard gain. But Jonathan Jones looked instinctive in his 10 snaps, making a nice run stuff for minus-4 yards and blitzing a couple of times. Perhaps he deserves more of a look next week.

Special teams

■  Speaking of Jones, he made a great diving play to keep the football out of the end zone and pin the Ravens on the 1-yard line, leading to Brown’s safety.

■  McClellin was being magnanimous when he credited his teammates for helping him block Justin Tucker’s 35-yard field goal.

But McClellin really just timed his jump perfectly. He was already halfway over the lone-snapper before the Ravens had gotten out of their stances and before the Patriots’ defensive line laid a finger on anyone. It was just incredible timing and athleticism from McClellin.

■  The absolute worst part of Cyrus Jones’s fumble was not that he allowed the ball to glance off his foot, but his outright refusal to go after the fumble once the ball was live. He just stood there and watched the play.

■  Patrick Chung and Julian Edelman should share punt return duties, while Dion Lewis should take kickoffs. Let the veterans handle it.