First half defense dug Boston a deep hole in Game 3 loss

Since the turn of the calendar year, the Boston Celtics have been the best defensive team in the NBA. It’s incredibly difficult to generate any half-court offense against a team that switches every action and has no weak link in the top-8 of their rotation. Yet, in Game 3 of the Eastern Conference Finals against the Miami Heat, the Celtics failed to execute their defensive game plan, or at least, to the level we’ve come to expect from them.

First and foremost, we have to accept that Boston’s bread and butter defense comes from the halfcourt, so when you’re giving up turnovers at a high rate, you’re putting your best foot forward from a defensive standpoint. The same can be said about forcing up tough shots because the Heat likes to run after grabbing a rebound, which doesn’t allow a defense to get set up.

Still, the Celtics had multiple halfcourt possessions where they could have bunkered down and made a difference, yet failed to do so due to miscommunications and/or over-aggressiveness towards the ballhandler. Let’s take a look at a couple of ways the Heat exploited Boston’s defensive scheme.

Defending the halfcourt PnR

With every halfcourt pick-and-roll, the Heat found an open man to help generate secondary actions or easy offense. In fairness, some of Boston’s mistakes usually go unpunished courtesy of Robert Williams’ presence around the rim. Still, the Celtics were exposed without their bouncy big man to fall back on, especially in the first half of play.

Take this play, for example, where PJ Tucker does an excellent job of initiating a second-side action that leads to a corner dribble-hand-off (DHO) for Jimmy Butler. Usually, the Celtics wouldn’t fall for the trap of sending two at the ball and would ensure one of their defenders stays situated near the corner shooter. But, as you can see above, after the DHO, Butler curls, and both Jayson Tatum and Daniel Theis go with him. Tucker ends up getting the kick-out and draining an easy three early in the game.

Honestly, sending two towards Butler isn’t a bad strategy, but one of the defenders needs to be “stunting” - taking a hard step towards the ballhandler before recovering towards their man. Collapsing onto one player in the manner shown above is not what the Celtics have built their defensive foundations on and hints to them being over-aggressive out of the gates.

This possession stood out to me the most when thinking about how Boston’s perimeter defense failed them in the first half of the game. Assuming the Celtics are instructed to switch on contact, the above possession would not have warranted Derrick White and Grant Williams changing their matchup.

However, you can clearly see Williams push Bam Adebayo into White to generate some contact, which in theory should trigger a switch between the two defenders. Instead, Williams steps onto the perimeter to guard the ball handler, Adebayo slips towards the nail, and White stays with his man, effectively creating a momentary double-team. Bam then gets the rock and finishes a layup almost uncontested.

To those of us watching on, this possession was the perfect illustration of the Celtics' “unconnectedness” with a communication breakdown, defensive scheme breakdown, and then a player (Williams) chewing out another player (White).

“We need to come out with more sense of urgency. Coming back home, you tend to relax a little bit, and I think we did that at the beginning. Finally, in the second (half) we started to play a little bit. You can’t spot a team this many points. It’s tough,” Al Horford told reporters when asked about Boston’s slow start and defensive lapses.

Of course, sometimes you can do everything right and still get scored on, but those are possessions you can live with. Take the above possession as an example, where the switch occurs on the strong-side corner, but Adebayo creates a mismatch with White. As the Heat big man drives middle, he engages Al Horford as the low-help man, leaving a wide-open shooter in the corner. Bucket. Still, the switch occurred, help came, and the Heat was forced to earn their points.

Corner actions created problems

No matter who was in the corner, the Heat looked to spring them free, primarily with pin-downs and DHO actions or flex actions (where a player screens towards the baseline for the player in the corner to cut baseline). Usually, when a team runs a corner offense such as this, the ballhandler curls around the perimeter looking for a scoring pocket or passing outlet.

Not the Heat. Instead, they were curling over their screener and driving towards the rim, forcing defensive collapses and multiple mistakes as a result. A lot of the Heat’s off-ball screens were also designed to get action flowing from the corners, with Tyler Herro a target for catch-and-shoot opportunities once the Celtics defense was put into rotation.

On the above play, we see the Heat run a zoom action but with the slight modification of the hand-off occurring at the elbow - something which is growing in popularity throughout Europe. The key difference in executing this set on the elbow is that it creates an additional pocket of space for the ball-handler to attack while also engaging the big’s defender, allowing them to create a lane for a roll towards the rim.

In this action, we see Adebayo and Herro run a corner DHO ‘Get Action’, which gives Herro plenty of space to attack the baseline, while Adebayo is occupying the defensive bigs, limiting their ability to protect the rim.

When the Celtics faced the Heat in the bubble, Adebayo cooked Boston’s defense with his high-post playmaking and how often he initiated corner actions for shooters like Duncan Robinson. And after two anonymous games to open the series, it looks like Erik Spoelstra tasked his multi-faceted big man with running similar actions in Game 3.

It’s hard to believe that Miami would have found this level of success had Robert Williams been in the rotation. Having the big man rotate over on the weakside to contest shooters or slashers has been one of the primary reasons factors in Adebayo’s early-series struggles. Still, you can only beat what’s in front of you, and the Heat won’t be bemoaning Williams’ absence, and the Celtics are unlikely to be searching for excuses at this early juncture of the series,

Looking ahead

While the Heat found success attacking Boston from the corners and slipping of ‘ghosting’ screening actions, their overall gameplan remained the same. Instead, Miami simply wanted to be the team to land the first punch and prove that the series was far from over.

“We talked about not being content or complacent with where we’re at and getting a win on the road. It’s more so a little unusual being caught off guard with physicality. It’s not like they changed much schematically, they just upped their pressure and upped their aggressiveness on both ends, and we didn’t match it,” Udoka told reporters after Boston’s game three loss.

Now, as we head into Game 4, the pressure is back on the Celtics, and they’re the team that’ll need to prove they’re still hungry for the fight, especially given the potential to be missing multiple players due to injury.

If the Celtics can match Miami’s aggressiveness from the jump and regain their defensive composure, especially from a communication standpoint, there’s no reason why they can’t tie the series up before heading back to South Beach. After all, the Celtics may have dropped two games, but those losses are from single-quarter collapses, and while that can be frustrating to hear, it should also be a great source of encouragement as we get deeper into the series.