“Depends if you play off a make or a miss,” Joe Mazzulla answered when CelticsBlog asked if there was a different game plan against the Cleveland Cavaliers’ zone defense. While this might appear insignificant at first glance, it captures the essence of Mazzulla-ball. The offensive strategy is a consequence of the previous opponent’s possession, meaning Mazzulla-ball starts on defense.
Defense comes first
For the last two seasons, Mazzulla-ball has predominantly been defined by two offensive characteristics: its three-point surge and mismatch hunting in elite spacing. The most obvious metric is the number of three-pointers attempted. For the last three years, the Celtics have attempted the most shots beyond the three-point line.
But, there’s another battleground where they’ve been dictating terms.
Since 2022, the Celtics have been one of the two best teams in the league at reducing opponents’ shooting efficiency. Over the last four seasons, they have ranked second in opponent eFG%, a testament to how dedicated Mazzulla-ball has been to defense.
Despite Ime Udoka being the head coach in 2021-22, Mazzulla had a significant influence on the Celtics’ defensive scheme in that deep playoff run. When joining the team in the summer of 2022, Malcolm Brogdon declared that Joe Mazzulla “was sort of the mastermind behind our defense and everything in the Finals.”
In 2021-22, the Celtics started the season poorly but turned it around in January by reconfiguring the defense. This drastic change emerged from Robert Williams III’s new role in the defense. The coaching staff, based on input from Mazzulla, turned the Timelord into a goalkeeper behind the defensive front line.
Robert Williams III is back at the TD Garden tonight.
Great timing to look back at 2022 when the Celtics turned their season around by using the young center as a roamer.
With Robert Williams on the court that season, Celtics' opponents were limited to a tiny 49.3% eFG%. pic.twitter.com/J49lLQMiyz
— azmatlanba (@azmatlanba) March 5, 2025
Joe Mazzulla’s innovative approach traced all the way back to his days running point at West Virginia and remain central to his coaching philosophy.
Shaping defensive tactics since college
If you’ve ever watched Joe Mazzulla play basketball, it’s obvious how much of a defensive-minded person he is. If you don’t believe me, here’s an example from 2011 where he puts Brandon Knight, a future NBA player, in jail. He puts a lot of pressure on the eighth overall pick in the 2011 NBA Draft, using his body and in mind to make it hard for him to even get the ball:
If you want to dig deeper into Joe Mazzulla as a basketball player, I wrote about it a few months ago. Not only was Mazzulla an active defender, but he excelled at reading the floor. When West Virginia beat John Wall and DeMarcus Cousins’ Kentucky team in the 2010 Final Four, they used a 1-3-1 zone. Who was behind that defensive approach? Joe Mazzulla.
Joe Mazzulla helped get WVU into the Final Four by proposing a 1-3-1 defense to coach Bob Huggins. Always had coaching pedigree pic.twitter.com/cbkxjuH5RJ
— Anthony Puccio (@APOOCH) June 18, 2024
Even after Ime Udoka’s departure, the Celtics remained an innovative and elite defense. Jrue Holiday’s defensive role change is a great example. Last year, Holiday discussed with Draymond Green how much Mazzulla has completely changed his way of playing and understanding basketball defense.
If you think coaching is just about calling a timeout at the right time (or if you think Joe Mazzulla only cares about offense), listen to Jrue Holiday talk about how Mazzulla has one of the best defenders in the game seeing defense in a whole new way. pic.twitter.com/xIcayOM63O
— John Karalis (@John_Karalis) March 27, 2024
Since arriving in Boston, Jrue Holiday has transitioned from a point-of-attack defender to a versatile defensive wrecking ball. He used to only be on the ball, navigating screens and putting pressure on ball handlers, but now his role has become much more varied. He has been used as a roamer like Williams, has defended Joel Embiid in the mold of Al Horford, and has even been placed at the back of a 1-3-1 zone defense—just like Joe Mazzulla back in 2010.
Jrue Holiday’s experimental role with the Celtics illustrates both Joe Mazzulla’s defensive vision and projects what he might have been as a player. On the court, Holiday embodies Mazzulla’s creativity, serving as his extension.
The innovation doesn’t stop with Holiday’s role. Look at Luke Kornet, who has been matched up with various ball handlers this season, like T.J. McConnell and even Russell Westbrook last week. If Mazzulla experiments so much on defense and places such a big emphasis on it, it might be because he has more freedom and influence on that end rather than on offense.
Controlling the game through defense
When Joe Mazzulla answers questions about the Celtics’ offense, he often says they are simply taking advantage of what the opponent’s defense offers. They focus on what they can control and make the most of it. But, on defense, the Celtics have more influence over what they can do.
There is more freedom in defense. Without the ball, you are free to move in any direction, at any speed, and occupy the floor as you wish. The only movement and spacing rule you need to follow is the three-second violation in the paint — even though it often feels like a forgotten rule in the NBA.
Since Mazzulla loves to focus on what he can control, it’s no surprise that he is so innovative on that side of the court. There are limitations to what you can do on offense. You have only one ball, and the only way to have a successful possession is to score.
On defense, however, you have more control, and there are multiple ways to win a possession. You can force a contested shot, generate turnovers in different ways, or turn a possession into a wasted 24 seconds. And, as Mazzulla said, offense depends on defense. So, by emphasizing defense, you give yourself a better chance to control what happens on the other end.
How does Joe Mazzulla build his defense?
As outsiders, we often give each coach a particular stereotype: Tom Thibodeau makes his players play hard and log big minutes; Erik Spoelstra always uses zone defense; Mike D’Antoni teams play fast. But is it really about the coach?
When CelticsBlog asked Mazzulla how he keeps coming up with new defensive strategies, he said, “I think you just kind of use what your players are able to do. We have a lot of versatile guys, that starts with them [...] it is utilizing kinda how fits your roster and what your guys are able to execute well as a team to be connected. But it starts with our guys’ ability to defend.”
Joe Mazzulla discusses with @azmatlanba the Celtics’ decision to utilize Robert Williams as a roamer defensively while he was in Boston, a change that played a pivotal role in the Celtics’ 2022 Finals run. pic.twitter.com/FIOGmXXvpo
— Bobby Krivitsky (@BobbyKrivitsky) March 5, 2025
What Mazzulla is making clear that no matter how dogmatic a coach may be, they always have to adapt to the players on the roster. Spoelstra didn’t wake up one day and decided to spam zone defense. It was possible because of Bam Adebayo and Jimmy Butler’s abilities and necessary because of Tyler Herro and Duncan Robinson’s defensive weaknesses.
What makes Joe Mazzulla such a great defensive coach is his ability to extract the most defensive value from his players and put them in their best roles, even when they didn’t know they could do it.
Jrue Holiday never had to communicate much on defense because he was the first cog in the defensive scheme before coming to Boston. Yet, Mazzulla saw potential for him to be more and helped him to evolve.
Because Derrick White was already on the team, Jrue Holiday’s skill set needed to grow into something more cerebral. Holiday became the quarterback and glue guy of one of the best defenses in the league, becoming a crucial component to Banner 18.
Mazzulla saw in Jrue Holiday, as he does in all his players, an opportunity to transform individual strengths and team dynamics into a new defensive scheme, one designed to confuse even the best offenses.
Joe Mazzulla is a disruptive mind whose lasting impact has been showing the league how he can give his players the best opportunity to thrive offensively through their defense. It’s what makes Mazzulla-ball work.
Since college, Mazzulla has been the hidden architect behind defensive strategies that gave his teams a chance to compete at the higher level. Once Brad Stevens handed him the keys, Mazzulla-ball took off, and hasn’t looked back.