How the Celtics Took Everything Away From the Mavericks in Game 1

So, I don’t know if I was expecting this kind of performance in the NBA finals. The Boston Celtics came out to play and executed on their game plan to perfection to blow out the Dallas Mavericks.

But it wasn’t the Celtics offense that blew the doors off. The best offense in NBA history wasn’t the reason they won this game. They did score 37 points in the first half and had a 148.0 offensive rating but that was it when it came to their offense — they followed that with 118.2, 95.8, 95.5, and finished the game with only 107 points.

The real story was their defense, holding the Mavericks to a 94.7 defensive rating for the game. This is the same Mavericks that was 8th in the regular season. This was their worst offensive rating in the playoffs — the only game that was sub-100.

In a very simple way to explain how the Celtics managed to do out is they didn’t allow themselves to get into rotations. That is it. There wasn’t anything that the Mavericks were doing that couldn’t have been defended straight up and as a result, not give up anything else.

It’s tough to get anything going on if there just isn’t someone needed to rotate because an advantage was created somewhere(we’ll see the difference in the Maverick's defense).

That shows up in a bunch of different stats(last game vs their playoff average)

• Catch-and-shoot 3PA: 13 vs 21.1
• Passes: 203 vs 251.1
• Potential assists: 25 vs 39.8
• Assists points created: 21 vs 57.7
• Drives: 48.0 vs 47.7
• % of drives passed: 29.2% vs 37.0%
• FGA off drives 29.0 vs 22.4
• % of shots within <2s: 28.6% vs 47.9%
• % of shots 2s+: 71.4% vs 52.1%

That is a significant change across the board in a number of different metrics. Their passing is down. Their off-the-catch 3s are down. Fewer kick outs available on drives. More shots are being self-created. That’s the basketball that the Celtics wanted to encourage.

So, let’s see how they managed to accomplish that.

It all starts with the pick-and-roll game and there are so many moving parts there. And to start, we got to look at the initial matchups, primarily looking at Daniel Gafford’s and Derek Lively’s.

This was Gafford’s defensive matchups sorted by possessions guarded(min of 4 poss):

• Jayson Tatum: 10.3
• Jrue Holiday: 7.4
• Al Horford: 5.3
• Jaylen Brown: 4.8

And here’s Lively’s

• Tatum: 16.7
• Kristaps Porzingis: 6.2
• Brown: 4.9

One thing stands out. It’s not Porzingis guarding the bigs. His defensive matchups looked like this:

• Derrick Jones Jr: 6.8
• PJ Washington: 6.7
• Lively: 6.2
• Maxi Kleber: 5.1

This meant a couple of things. If Doncic wanted a screen from his bigs(Gafford or Lively) to have his roll man and a lob threat, that would be putting any of Brown, Holiday, Tatum, and Horford in actions.

If you’re putting them in action, that is a simple switch and now you’re encouraging just isolations.

The way the Celtics defended that is straight up and not offering much help. You can see in the first clip with Derrick White looking to help but then immediately recovering back. And in all the other clips too, there’s help showing, but only ever so slightly. Even if the pass would be made, they don’t have to close out that far to be put in rotation.

This is where both Doncic and Kyrie Irving have to be a lot better. I didn’t think they punished the Celtics defense effectively whenever they were going to work in isolation — whether that was settling for tough shots or missing bunnies at the rim.

Some of the looks, you can see that they are shots that either of them makes in their sleep. There’s that Irving drives vs Horford at the 25s mark or that layup he smoked vs Pritchard at the 46s mark. Or maybe you have Doncic blowing a layup at the 1:06 mark. All easy, good looks.

But the way the Celtics defend them still pops out. On some of those, they’re not rotating to show any kind of help. Look at the first clip early in the game, where is Doncic meant to pass? It’s forcing them to beat you being a scorer. That’s how the Celtics have defended throughout the playoffs. They’ve been a team that is reluctant to show any strong help.

Now, that wasn’t the case all the time. They did show help when needed but they did it in such good timing, especially with Porzingis. Look at the 1:01 mark Doncic has the drive but you also have Lively in the strong corner, so Porzingis is able to deter a shot and force a turnover.

Doncic will have to be better in that area because there was a lot of hunting going on when it comes to Sam Hauser and Payton Pritchard, but they held up. They did their job. Hauser forced a turnover and didn’t give up anything other than a contested 3pt.

When it comes to picking on Pritchard, the Celtics just executed so well to not give anything up. Doncic had Pritchard on him early and had the drive baseline but you can see White quickly coming to double and managed to kick the mismatch out. Similar thing at the 42s mark. He gets Pritchard on him but then another great read from White to strip him as he looked to attack from behind.

This was the main reason how they were able to stop the offense. Switch almost every pick-and-roll by having the matchups lined up well. They weren’t overhelping or showing help on potential drives. They prioritised staying with shooters. Their “liabilities” held their own and everyone else executed well to take away those advantages before they even happened.

There is also the Porzingis factor too. As much as the Celtics wanted to keep him away from the actions, he was still involved and effective. Now, their main goal was to keep him away from the actions. They did so by stashing him on all of the wing players and have him remain in the paint.

The Mavericks shot 12/16 at the rim and 7/17 in the short mid-range(4–14ft) when Porzingis was off the floor. That’s 57% within 14ft. That dropped to 4/9 at the rim, and 3/9 in the short mid-range. That’s only 38%! That’s the Porzingis factor. He protected that paint.

The first thing is how they treated the roller/popper. Watch the clips at 15s, 24s, 39s, 44s, 57s, and 1:35. Because Porzingis is guarding the wings, they’re able to play him in high drop vs Doncic to take away his drive to the rim and any shots. But at the same time, don’t allow any lob or pop to punish them either.

And when he is being used as the screener, that also means that none of the bigs are! If none of the bigs are being used, then what are you doing with Gafford or Lively? They’re ruining the spacing.

Though this wasn’t all perfect and this is the button that the Mavericks need to push. The Mavericks will somehow figure one of 2 things. How to get Porzingis off the wings? Or how to punish them when he’s guarding them?

We can see in the first clip where the Celtics looked to show with Porzingis when Tatum was on Doncic. When you show like that, Doncic is splitting the defense and is getting to the rim. I’m not sure what the goal was with him showing.

But there was more good things when attacking him. At the 35s mark, they were able to force the switch. Similar thing at at the 1:05 mark — all involving Brown. They will need to do a better job at eliminating or making the job tougher for the screen navigators to get over that first screen to force a switch. In that second clip mentioned, you can see Doncic perfectly snaking the PNR to get the switch.

This play also stood out:

Any time both Horford and Porzingis are on. I want to see this.

Finally, here are some other defensive plays from the Celtics that stood out to me that were all equally as important:

First, you have the extra ball pressure from Holiday. Doncic did have four turnovers. Whether or not a turnover is forced, the goal is to just waste more time. The Mavericks for the playoffs are shooting 38% on shots under 7 seconds on the clock. Any seconds you can kill off the clock by that rim pressure is key.

You also have Brown’s weakside rotations. There were a few plays that gave the Mavericks an advantage but it didn’t matter because Brown was there to clean it up. That’s not just a Brown thing — they have Holiday, Tatum, and White all capable of being that effective weakside help.

That just speaks to the Celtics overall connectedness on defense. Related to that is their pre-switching. One way of keeping Porzingis out of the actions is by pre-switching. That’s what he did with White and Pritchard a couple of times and what that did is again encourage isolation whilst having Porzingis near the rim protecting it.

Overall, this was one hell of a defensive strategy and execution from the Celtics. They did almost everything perfectly. There was a third-quarter relaxation in a way where they did give up many drives to the rim, but that felt a lot like stepping off the gas.

To me, what they showed with their defense poses so many questions for the Mavericks to solve and they’re tough to solve.

In the non-Kristaps lineups, they can switch everything without giving much up. They can take away all of the rolls and lobs. They’re making Gafford and Lively ineffective on both ends.

Whenever Porzingis is on, that’s even worse. If it’s a PNR against him but it’s a wing setting the screen, that doesn’t do much. And it also means there’s extra help in the paint because of non-shooters being there. This is still their best bet in putting them in any kind of rotation but it’s a big issue to be solved.

One thing has to be considered, though. That’s simply, Doncic will play better. They left a lot on the table when it comes to their isolation attacks. I wouldn’t be surprised if that kind of defense will be severely punished by them. I don’t know how high my trust level is in Horford’s defense like that.

But as it stands, the Celtics have the upper hand in so many ways defensively and it’s going to take a lot to solve it.