TORONTO — The year before Steve Kerr arrived, the Mark Jackson Warriors gave up 99.9 points per 100 possessions, the third best defensive efficiency rating in the NBA.

Kerr came in and reworked an offense that, despite immense talent, was middling. Those tweaks elevated the Warriors into title contention. But they wouldn’t have stayed there without a defense that remained dominant. Kerr left it untouched and, the past two seasons, Golden State, with its engrained core and schemes, pumped out 98.2 and 100.9 defensive ratings, first and fourth best in the NBA, respectively.

“They already had their defensive style,” Kerr said. “We didn’t change anything about the defense. There was already continuity.”

This season is different. The Warriors have a new star, another new starter and a batch of new bench players. Along with the personnel, some terminology and schemes have changed. An adjustment period was expected. Ten games is a minuscule sample size. But the early defensive results, despite an 8-2 record, have been underwhelming.

Every NBA title-winner the past 10 seasons has produced a top-10 regular season defensive efficiency rating. Despite a soft schedule, the Warriors entered Tuesday tied with the Brooklyn Nets for 14th, giving up 104.6 points per 100 possessions. So what’s wrong? Let’s look at some film of Golden State’s last game — a 133-120 shootout win over the 3-8 Suns — to get a better idea.

Shot-blocking?

Everyone wants to point to the Warriors’ lack of rim protection. Ground-bound Zaza Pachulia and David West replaced the more defensively imposing Andrew Bogut and Festus Ezeli.

Last season, the Warriors held opponents to 50.4 percent on shots at the rim, the fourth lowest in the league. This season, opponents have upped that to 54.4 percent, the eighth highest.

Pachulia, in particular, has struggled to bother attackers. Opponents are shooting 67.7 percent against him at the rim. Among the 66 players who contest at least 4.5 per game, no one is giving up a higher conversion percentage, per NBA.com/Stats.

West, at 50 percent, has been better but still not great. Neither get up vertically and provide any type of in-air deterrence. So when Klay Thompson gets beat baseline, like in the clip below, Brandon Knight has no issue cruising in for the no-fear layup as West rotates over.

But there’s no rule that says your center has to be your primary shot-blocker. The Warriors still have scary athletes all over the floor. Draymond Green is averaging 1.6 blocks per game, 11th most in the league and third among forwards, behind only Anthony Davis and Giannis Antetokounmpo.

Kevin Durant, at 1.4, is right behind him, making the Warriors the NBA’s only team with two of the league’s top 15 shot-blockers. As a team, Golden State averages 5.7 per game, the sixth most.

How? The personnel changes have swung both ways. Go back to a memorable sequence late in the third quarter of the Suns game. Rookie Patrick McCaw, who is quickly earning a heftier rotation role, tracked Devin Booker on a drive and spiked his layup off the backboard, an incredible defensive play from a guard.

Moments later, after a Warrior transition miss, Booker had what seemed to be an easy cherry-pick layup. But Durant flew in out of nowhere to stuff it away at the last moment. Can you imagine Harrison Barnes and Leandro Barbosa — the two players Durant and McCaw replaced in the rotation — combining on this sequence below?

Perimeter energy issues

Pachulia has shouldered a brunt of the public blame. And the Warriors have struggled with him on the floor: a 107.5 defensive rating in his 170 minutes. But he’s been far from the only issue. In Pachulia’s 310 minutes off the floor, the Warriors defensive rating is 103.1, still far below their recent standards.

“We’ve got a lot of talented individual defenders,” Kerr said. “But at this point, we haven’t had five guys on a string consistently.”

Consistent effort and focus seem to be the biggest issues, even for the spectacular Draymond Green, who appears on his way to another high Defensive Player of the Year finish. Check him out just snoozing on this key late third quarter possession. There are no other breakdowns. T.J. Warren just slips by him before Green even notices.

Those kind of lax plays have burned the Warriors off and on over the first 10 games. They’ll go up 30 on a skeleton Mavericks team, then take their foot off the gas and give up a 20-6 run in a blink. And nearly everyone has been partially to blame.

Here’s the first play from the Suns game. Right off the tip, Eric Bledsoe tricks Stephen Curry by reversing to the left corner after a baseline screen. A head-down, jogging Curry notices way too late, leaving Bledsoe by himself. Green has a chance to help, but doesn’t. Bledsoe cans an easy 3.

Then there’s Klay Thompson, who has earned a reputation as one of the strongest, sturdiest, consistent defensive shooting guards in the league the past couple years. But he’s had some early-season shooting struggles and, as he admitted, those offensive woes have occasionally bled into other areas, including defensive focus. It really hurt the Warriors throughout the Lakers loss.

Here’s a first half possession from Sunday night. The play before, Thompson was called for an offensive foul. Walking down the court, he looked frustrated. Then on the defensive end, he just kind of floated around, appearing distracted. Track him on the left wing, as his breakdown leads to a wide open Jared Dudley jumper.

Transition recognition has been an issue as well. Watch this play below for example. Kevin Durant falls on a drive, leaving him behind and the Warriors facing a 5-on-4 disadvantage. The Suns push it up to Bledsoe, as Booker slides to his left, wide open on the wing. Booker is a far deadlier 3-point shooter than Bledsoe, but Curry and Green don’t seem to recognize the development quick enough. Both stay glued to Bledsoe too long and Booker gets an open 3.

Spurts of dominance

There are no regular season records to chase. Golden State, maybe more than any other title contender in recent memory, was delivered the cruelest of reminders last June: What you do November through mid-April doesn’t matter much if you don’t finish

Golden State wants to be crisp come playoff time. These months help cultivate that. But human nature often sets in during the NBA slog. Possessions and quarters and sometimes games are taken off. But it’s important to occasionally remind that a flip can be switched.

Through the first 10 games, despite the struggles, the defensive ceiling remains high. When flying around, their length, activity and athleticism can terrorize. They closed the Suns out on Sunday with a 25-6 run in the final 5:48. Phoenix missed six of its last seven shots and turned it over three times.

Here are a pair of high-level defensive possessions. In the first, McCaw — active and long and, so far, almost always locked in — hounds Booker way out on the perimeter, throwing the play out of tilt from the jump. As the Suns work it back to the middle with a series of screens, Durant jumps out to help McCaw, Green rotates to help Durant and then Durant recovers in time to draw the offensive foul.

On the second, the undersized Green stones an Alex Len post-up and strips the ball. Warren picks it up, but McCaw tracks him and comes up with another strip. It falls into Len’s hands again. Green strips him again, this time springing a Warriors fastbreak the other way, which leads to a Durant 3, the kind of offense-to-defense play that makes this team so dangerous.