Finals Film Study: How Celtics Take Control in Game 1

Al Horford made the Warriors’ defense pay by having a career night off.

The Golden State Warriors were the No. 1 defensive team in the league when Draymond Green was healthy this season. With Green missing two months with a relapse, the Boston Celtics took (and retained) first place. But Golden State was so good when Green was healthy (they allowed 1.9 fewer points per 100 possessions in his last game before the injury on Jan. 5), they only dropped to No. 2 in the final week of his two-month absence .

Shortly after Green returned, Stephen Curry lost a foot injury. But the Warriors’ two stars, along with an improving Klay Thompson and the other three guys in their top six, were available throughout the playoffs. And that’s their sixth time in eight years in the NBA Finals.

Full Coverage: 2022 NBA Finals

Still, the Warriors’ defense couldn’t reach the level it was at in early January. And Game 1 of Thursday’s Finals was the team’s third-worst defensive performance of the season, with the Celtics scoring 120 points on just 93 possessions (129.0 per 100). The only two games in which a team scored more efficiently against the Warriors were a visit to Dallas in March (without a green) and Game 5 of the conference semifinals in Memphis, a 39-point loss. Game 1 was the first time in 51 home games that the Warriors had allowed at least 120 points per 100 possessions, and they had allowed more than 130 per 100 before the Celtics ticked off the clock on their last possession of the night.

The Warriors were in the bottom five of their opponents’ free throw averages during the regular season, but free throws weren’t really an issue Thursday. The Celtics’ free-throw rate (16 free-throw attempts; 85 field goal attempts) was both the third-lowest of the playoffs and the third-lowest the Warriors have conceded in the playoffs.

The Celtics also created a few second chances, but their offensive success relied primarily on their shots from the field, including an incredible 88.6% field goal percentage in the fourth quarter. Boston has certainly surpassed theirs expected effective field goal percentage (based on the quality of shots they took) by a healthy margin. But while they made some hard shots, there was a lot more going on as the Warriors allowed them to score more efficiently than the Brooklyn Nets in every first-round game.

Here are some stats and a movie of the Celtics’ Game 1 offense:


1. Five out

After giving Curry too much room to shoot early on, Robert Williams III had a better second half defensively. He blocked a Curry stepback, then turned in time to block the Warriors star on the rim.

Still, the Celtics were better when Williams was off the ground, and that was largely due to their offense. They scored just 32 points on 34 possessions (0.94 pro) with Williams and Al Horford together on the floor, but 48 to 34 (1.41 pro) with Horford on the floor without Williams.

With Horford at 5, the Celtics had five guys who could shoot and make the Warriors bigs pay for protecting the paint.

Towards the end of the second quarter, Green zoned in the paint as the Celtics executed pin-down action down the left side of the floor. Green’s presence kept Marcus Smart from passing Derrick White under the basket when Curry was turned over and it also allowed Andrew Wiggins to lock Jayson Tatum from above while Horford put up another screen knowing Green was there was when Tatum walked out the back door.

Since Horford has the ability to shoot himself, Tatum took on the role of screener and put a pick on Green in the suit when Horford jumped out to the wing. Wiggins realized what was happening half a second late, and Horford emptied the second of his six career 3-point records:

Al Horford 3-pointer

The Warriors’ small ball look with green on the five has been extremely successful for them over the years. But the Golden State small-ball look still has at least one guy (Green) who doesn’t shoot well (or often) from the perimeter. The Warriors were down-13 (62 points from 43 possessions) in a little under 22 minutes with Green at the 5 on Thursday because the Celtics’ Horford-at-the-5 lineup was better.


2. The 3s were open

According to Second Spectrum tracking, 23 (56%) of the Celtics’ 41 3-point attempts were wide open*. That’s a higher odds than three of the Celtics’ four games against Brooklyn in the first round, and the Nets were Not good at defending the 3-point line.

* According to Second Spectrum, 48% of league-wide 3’s were wide open during the regular season. That was the Celtics’ odds in both the first round (overall) and conference semifinals against the Milwaukee Bucks (who have allowed the most 3-pointers in each of the last four seasons). Only 32% of Boston’s 3-point attempts were wide open in the Conference Finals.

Some of these are the warriors who allow certain shooters (Horford and White were responsible for 13 of those 23 wide open attempts) to fire. Even though White had already made a 3, Green didn’t urgently close against him early in the second quarter:

Derrick White 3-hand

In the first three rounds, White was only 13-44 (30%) with 3s wide open, so you can understand the warriors’ willingness to let him shoot.


3. All eyes on Tatum

Tatum was just 3 for 17 (18%) in Game 1, his worst shooting performance in 69 playoff games of his career. And he definitely missed a good look, going 0-on-3 on those wide-open 3s that the Warriors allowed. But the Warriors also showed him a lot.

The Celtics often attempted to pair Tatum with Curry. According to Second Spectrum, the guy Curry was guarding put up seven ball screens for Tatum, while Tatum put up eight ball screens for the guy Curry was guarding. But the Celtics only scored 10 points on those 15 chances.

When Tatum isolated or posted against Curry, the Warriors were ready with help. Heck, even with Tatum isolated against Green (arguably the best defensive player in the league), Curry snuck away in the corner of Payton Pritchard’s strong side to provide assistance:

Stephen Curry Defense Aid

And while Tatum did force some things, he generally made the right play, and Thursday’s 13 assists marked a career high (435 games total, including regular season and play-in). He scored 35 points from his assists and also one of Horford’s wide-open 3s through a great body kick-out, cross-court and a swing pass from Smart:

Al Horford corner 3-pointer

The Celtics scored 108 points on 82 possessions (132 per 100) with Tatum on the ground and (even if you discard that last possession of the game) only 12 points on 13 possessions with him off the ground.


4. Error

The Warriors also had some glitches. Right after Otto Porter Jr. took them to 14 with a 3 late in the third quarter, Horford was wide open in the corner with Green hanging in the paint:

Al Horford corner 3-pointer

While White hasn’t shot well in these playoffs, Horford has. In the first three rounds, he was 28-60 (47%) on wide-open 3s. Now he’s 33-for-66.


5. Awesome!

According to Synergy tracking, the Celtics were the most efficient team, scoring 1.03 points per possession outside of time-outs. And another of her seven 3-corners came on her first possession in the second quarter via a “hammer” play, with Daniel Theis setting up a weak backscreen for Pritchard, Grant Williams delivering the cross-court pass and Green ( back in the suit hang) react only half a second too slowly:

Celtics hammer game

Gibson Piper has a good breakdown of this killer game (and others) here.

The league has averaged about 3.3 corner 3s (per team) per game this season. The Warriors have allowed 23 in their last three games.

Overall, the Warriors have allowed 123.8 points per 100 possessions over those three games, the most they have allowed this season in a three-game streak with Green in the lineup. You can certainly believe that the Celtics won’t shoot more than 50% from the arc again, but they should also believe that they need to be better defensively in Game 2 on Sunday (8ET, ABC).

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John Schuhmann is a senior statistics analyst for NBA.com. You can email him here, his archive can be found here and Follow him on Twitter.

The views on this page do not necessarily reflect the views of the NBA, its clubs, or Turner Broadcasting.

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