Warriors’ defense sets the tone as Steve Kerr pushes the right buttons to seal the deal against the Celtics

Synergy tracking has counted only two teams in the NBA who have trapped around pick-and-rolls this season: the Golden State Warriors and the Brooklyn Nets. The total number of traps the Warriors have tallied (44) and the total number of traps the Nets have tallied (11) is a chasm — but the Warriors, curiously, have allowed opponents to score 1.175 points per possession on a trapped pick-and-roll, which isn’t a particularly good number to be giving up.

However, the Warriors have used their trapping scheme to set the tone for the rest of their defensive efforts in a given game. Trapping (otherwise known as “blitzing” or “doubling around a screen”) has its pros and cons, just like all pick-and-roll coverages. As mentioned, trapping can engender high energy, high awareness, and promote full focus and intensity out of the gates. It can expose ball handlers who aren’t the most astute decision makers when placed into sticky situations. At the very least, it can take the ball out of their hands and funnel the decision-making and scoring responsibilities onto someone who isn’t as capable in those departments. It can speed up teams who prefer to play a slow and methodical half-court game, forcing them into mistakes they’re not accustomed to making.

The plan worked in the first half against the Boston Celtics, who turned the ball over 10 times — 20.4% of their offensive possessions, uncharacteristic given that they are the best team in the league at minimizing turnovers (11.1% turnover percentage). But it takes a special team — or the makings of one — to make the defending champions and favorites to repeat highly uncomfortable and flash their bad form.

The Celtics looked unprepared to handle the Warriors’ traps out of the gate. In particular, Jayson Tatum’s trap-handling chops were tested right away:

A subtle part of why the Warriors’ traps have been successful and rarely taken advantage of is the presence of a “roamer” at the nail, who perhaps has the toughest job on the backline: tag any rollers acting as release valves, close out quickly on poppers, and keep tabs on the weak-side wing and corner while initiating a potential “X-out” rotation, if needed.

The short roll above was covered by Moses Moody — and he performed his role brilliantly by rotating toward Neemias Queta and forcing the turnover.

Fast forward five minutes later— the Warriors spring another two-to-the-ball coverage against Tatum, with another small wrinkle added in. When Draymond Green’s man comes up to set the screen, listen carefully to what he yells to Andrew Wiggins:

Green yells out “weak” twice — not to hurl an insult toward Tatum, mind you, but to inform Wiggins of the “Weak” pick-and-roll coverage, the definition of which is self-explanatory: Wiggins placing himself between Tatum and the screen, shading him toward his weak hand (left), and having Green there to help with the coverage. Tatum does manage to find Queta, but Gary Payton II is there to rotate and put his hands on the ball, which baffles Queta and forces him to pass out to Horford. Buddy Hield is there to make him think, and Horford’s hesitation costs him his shooting rhythm.

It wasn’t only Tatum who was given the trapping treatment. The Celtics employ Derrick White occasionally as the lead ball handler with Tatum on the bench, while also running action that gives their bigs decision-making reps up top and at the elbow — not unlike the Warriors themselves, although not to the same extent and volume. One of those elbow sets involve the split-action concept, something the Warriors have been all too familiar with. Nowadays, they’re finding themselves having to defend it as its usage has become more popular and ubiquitous.

In the Warriors’ case, familiarity breeds effectiveness. Watch as the ball is fed to Luke Kornet on the elbow, after which White and Payton Pritchard try to run split action on the opposite slot:

Based on the personnel involved, a switch between Hield and Lindy Waters III seems to be the correct coverage choice, But with Waters staying in contact with White and Hield keeping close tabs on Pritchard around the guard-guard screen, a switch ends up being unnecessary. Kornet and White then default into a pick-and-roll, but Waters and Trayce Jackson-Davis surprise White with a sudden blitz, pushing him out all the way to the half-court line and forcing him to make a desperation pass to Pritchard — who steps on the line.

However, a team fresh off of a championship and who has been continuing their elite ways is bound to make adjustments. It was a matter of time until the Celtics took the data the Warriors were giving them and react accordingly. As much as traps can catch a team unawares, it often has an expiration date against teams at this level, let alone an inner-circle contender who happens to be the best offense in the league heading into this game (127.1 points per 100 possessions).

As such, the Celtics’ patience with regard to moving the ball and finding a good look — a hallmark of their offense this season and last year — eventually rewards them:

While also finding a small-yet-significant chink in the Warriors’ trapping armor. Whenever the Warriors have their big step up to trap or align themselves to the level of the screen, it makes them vertically compromised on the backline — and highly vulnerable to offensive rebounds, especially from a team fond of crashing from the corners.

Joe Mazzulla also dialed up a few “Stack” or “Spain” pick-and-roll sets where a shooter (Sam Hauser, in this case) sets a backscreen on the screener’s defender — only that Hauser didn’t intend to set the screen but instead leak out to the wing and catch his defender between a rock and a hard place:

As a result of the Warriors having to bring their bigs up top to trap with no defensive rebounding support behind it, the Celtics were able to haul in eight of their 13 offensive rebounds in the third quarter alone — and scored 14 second chance points off of them. It also didn’t help that the Warriors started a habit of ball watching instead of crashing and boxing out. With Mazzulla making the adjustments he needed to take away the Warriors’ penchant for aggression around ball screens, the ball was now in Steve Kerr’s court to respond with the counter-adjustments to take away what the Celtics were doing effectively.

With the game on the line and the Warriors having stayed in close contact with the Celtics, Kerr chose to close the game with Kevon Looney — a move to remedy the rebounding problem while also giving the Celtics a dose of their own medicine on the offensive boards. With Jackson-Davis not being effective as a rebounder and the prospect of Green at the five not solving the immediate problem, Kerr decided to press the Looney button and count on his reliability.

In an effort to keep the Warriors offense contained and flat, the Celtics also began to switch everything that involved Curry. While switches are far from being as risky as outright traps, it does present the same risk of giving up an offensive board when bigs are brought up to switch onto Curry, which is why Horford was brought in at the four in a double-big setup. When Queta switches onto Curry on the off-ball away screen — with Horford “guarding” Green — Curry finds his longtime partner in crime unmarked in the corner. Horford is compelled to make a close-out and contest, which draws him away from the paint. Queta tries to recover for the rebound, but Looney gets there first and is helped by a bit of airball luck:

On the next Warriors offensive possession, Queta is once again brought up top to guard ball-screen action for Curry. With only Horford to box out and — and in an ironic twist of fate — the other Celtics players ball watching and not making an active effort to track down the board, Hield hauls in the long rebound and gives the ball to Curry. Curry badly miffs the layup — but once again, Looney is at the right place at the right time:

When the Celtics shift a few of their pieces around to prevent Queta from being brought up top and away from the paint, the Warriors resort to targeting Horford on a mismatch against Curry. Past matchups — notably during the 2022 NBA Finals — have historically given Curry an edge over Horford whenever he switches out on the perimeter against the Warriors superstar. But the Celtics aren’t keen on playing any sort of drop coverage, nor are they willing to put themselves in rotation against a lineup with Hield and Wiggins stretching the floor.

They are willing to live with Curry dancing with Horford in isolation and sending appropriate help when needed — such as gap help in the form of stunts and digs at Curry’s drive, which is what Tatum is expected to do when Curry enters his defensive orbit. However, watch Tatum, whose assignment is Hield:

Tatum falls asleep and loses track of Hield — all while doing practically nothing to deter or stifle Curry with any sort of gap help. Hield drifts to the corner with no one switching onto him, and drills what would become the dagger three.

This statement win was a test of the Warriors across the board — their players as well as the coaching staff. Kerr pushed the right buttons to secure the win for the Warriors; the players executed the coverages and stayed the course when the Celtics made their furious-yet-expected rally. When push came to shove and the Celtics were asking questions of the Warriors’ true contender status, they were able to pass with flying colors, all while flying at the hoop to get the rebounds they needed to seal the deal.