The duality of the Celtics’ defense

For the majority of the season, the Boston Celtics have looked like the best team in basketball. But as was the case at the start of last season, they routinely slide backward, falling into bad habits and suffering embarrassing losses. Both versions of the Celtics’ defense were on full display in the span of just three days.

On Tuesday, the Celtics lost to the Oklahoma City Thunder 150-117. It was their worst showing of the season, as Boston failed to deliver any semblance of energy, allowing the Thunder to set a franchise record in points.

Two days later, they stomped the Dallas Mavericks, earning a 124-95 victory. Jayson Tatum recorded the second triple-double of his career, and the Celtics held Luka Doncic to 7-of-23 shooting from the field.

The Celtics put together one of their most impressive wins of the season, the game after their worst performance of the year. It’s that duality that can take away from their best-record-in-the-NBA greatness. At their best, the Celtics are one of the favorites to win the NBA championship. At their worst, they let the Shai Gilgeous-Alexander-less Thunder score 150 points.

Don’t get it twisted. Oklahoma City is a tough team. Despite the popular notion about their status in the Victor Wembayama sweepstakes and Sam Presti’s affinity for draft picks, Mark Daigneault has organized an energetic group of youngsters that fights hard night in and night out. But the Celtics shouldn’t allow 150 points against any team, let alone an injured OKC squad.

The loss to the Thunder and the win in Dallas have far more to do with Boston’s inconsistencies than the level of play of either opponent. One night, the Celtics could be locked in, communicating well, and hitting their rotations on every play. But the next, their defense is full of holes and no one is talking.

Boston’s defense let Oklahoma City have its way with them. Heading into the game, the Thunder ranked 24th in the league on offense, but against the Celtics, they were getting into the paint at will and nailing wide-open three-point shots.

This play is a great example of how miscommunication and defensive lapses can lead to easy buckets. Grant Williams gets thrown into a pick-n-roll, and at first, he gets ready to switch with Tatum. Once he realizes Tatum didn’t switch, he turns back around, only to get caught on the same guy as Sam Hauser. Jalen Williams waltzes into the paint for a bucket.

Williams is the main player at fault here, but it’s also a result of an unclear gameplan. Tatum doesn’t yell out to Williams to stay put, only providing him with a last-second shove to get him back into position. Hauser is so zeroed in on Isaiah Joe that he doesn’t realize what’s happening behind him. It was just a mess of a play by the Celtics.

Lack of communication and general laziness allowed the Thunder to run rampant in the paint. Yet in Dallas, the Celtics were stellar on defense. The Mavericks were missing some easy looks, yes, but the communication and overall intensity kicked up a notch.

Don’t just watch this play - listen. It doesn’t end in the prettiest contest, but Al Horford baits Doncic into taking an awkward layup, as the Mavericks star was leaning in an attempt to draw contact. But it’s the build-up to Doncic’s shot that’s important to note.

The Celtics are talking, making sure everyone is in the right position. Dallas sets an odd double screen for Dinwiddie, leaving Tatum on him, Malcolm Brogdon on Tim Hardaway Jr., and Derrick White on Christian Wood. White fights for position, not allowing Wood to get a clean look in the post. Horford eventually comes over to help, and Marcus Smart covers for him on the weak side. Smart is constantly yelling at his teammates and ends up helping Horford get into the perfect position to meet Doncic at the basket.

It was extremely clear that the Celtics went into their tilt against Dallas with a better mindset and a more defined gameplan. In a weird way, the presence of Doncic helped them on defense. They knew who they were trying to slow down, and they ended up up throwing doubles at him all night. It left them scrambling in rotation, but their communication was so on top of things that it didn’t matter.

Just watch. Brogdon doubles Doncic in the corner, leaving Hauser to shift over to Frank Ntlikina. Boston was letting one player cover two guys all night because of these double teams, and on this play, it’s Tatum. In an ideal world, Williams makes his way over to the corner, but since he’s tangled up in the post, Tatum is left to challenge Hardaway, and he gets a great contest off.

This sort of defensive effort was completely absent against the Thunder. Not only were the Celtics careless, but they were silent. There was no communication, and, in turn, Oklahoma City shot 20-of-40 from behind the three-point line. Boston’s rotations, or lack thereof, allowed the Thunder to shoot 16% better than average from distance.

Here’s a perfect example. First, Tatum bites at a pump fake by Joe from nearly three feet behind the arc (an issue in and of itself), and that leads to chaos. Joe gets a free lane to the hoop, leaving Horford to contest in the paint, but no one covers for him. Brogdon and Jaylen Brown get caught ball-watching, giving Kenrich Williams a free look.

And since the difference was so stark, here’s another pair of opposites.

Effort and communication:

Laziness and silence:

Just last season, Boston laid claim to the best defense in basketball, and over the second half of the year, it wasn’t particularly close. Having Robert Williams consistently in the lineup obviously helped, but the issues Boston is having on defense are largely to do with their effort.

Boston’s offense was elite at the beginning of the year, and their defense began to turn the tide in December, but only one of those things is completely in their control. They can’t always control whether or not shots are going to fall, but the Celtics can always control how hard they try on the defensive end. The saying “defense wins championships” is very overused (and not entirely true), but there is something to be said about one side of the ball being more dependable than the other.

The Celtics’ offense is what’s going to make them the best team in the league. When the ball is zipping around and they’re hitting their shots, it’s extremely tough to stop them. However, their defense is what’s going to help them raise the floor. Without that foundation to stand on, everything crumbles.