Robert Williams III delivers for the Celtics, Joe Mazzulla in crucial game 6

Yaron Weitzman

FOX Sports NBA Writer

PHILADELPHIA – The press conference has ended, Joe Mazzulla had a question for the reporters in the room.

His Boston Celtics had just defeated the Philadelphia 76ers in the second game of their Eastern Conference semifinals game, and Mazzulla was conscious of the public criticism he felt as a 34-year-old first-time head coach. He was unprepared for that moment, and especially because he had failed to make the correct adjustments in the game, he wanted to make it clear.

“No one wants to ask about all the adjustments we made from Game 1 to Game 2?” he asked reporters before storming off the podium. His face was serious. That was a comment, not an attempt at sarcasm.

About a week later, with Mazzulla entering Game 6 and his Celtics faltering and one loss away from elimination, he decided to make a change. This adjustment would be big in that it would swap one security guard – Derrick White – for another big man. However, not just any great man. Robert Williams III One of the best rim protectors in the league, a player whose on-court presence and chemistry with tall colleague Al Horford helped propel last season’s Celtics to the Finals.

“Give us a different look,” Mazzulla replied during his pre-game press conference when asked why he was changing the lineup. “Rob gives us a boost when we’re at our best, especially defensively. Just his presence on the sidelines, his ability to defend and rebound.”

Before the game, Mazzulla shared his decision with his players.

“I was thrilled,” said Celtics guard Marcus Smart. And just a few minutes after the hint, it was clear why. Thanks to their defense, the Celtics kept their season alive with a 95-86 win in Game 6 in Philadelphia on Thursday and set up a Game 7 win or home win in Boston on Sunday.

Williams finished the game with 10 points, nine rebounds and two blocks in 28 minutes of play. In those minutes, the Celtics surpassed the Sixers by 18 points. In 19 minutes that Williams and Horford shared the court, the Celtics posted a 25.1 net rating.

“Tell you what,” Horford said after the game, “I’m glad Joe made that adjustment and we made it because what a difference.”

“For Rob to be there, he changes the game,” Smart said.

“It’s made a tremendous difference,” said Jaylen Brown.

“Even if he doesn’t block shots, doesn’t mark his presence or changes shots, it makes a difference,” said Jayson Tatum.

When Mazzulla took over for the suspended Ime Udoka, he left the group of two that Udoka had ridden the previous year. The pair had played just 332 minutes together during the season and although they’d beaten their opponents and outscored them by 15.9 points per 100 possessions, Mazzulla prefers to compose his lineups with an offensive side of the floor in mind. He believes good offense is the foundation of good defense – and having a non-shooter like Williams on the field prevents the Celtics from five-outing. The Celtics finished the regular season second in the league on both offenses And Defensive efficiency was hard to dispute.

But the playoffs are different, and in the playoffs the Celtics’ defense had fallen off a cliff. By the start of game six, they had yielded 114.2 points per 100 possessions, a number that would have ranked 19th in the NBA in the regular season. In Game 5, James Harden and Joel Embiid had them out in the pick-and-roll.

Williams’ presence changed everything. The Celtics edged him out at the basket, leaving Sixers forward PJ Tucker, a reluctant and shooting shooter, open in the corner. While Williams lay in wait, Harden – who scored just 13 points, missed 12 of his 16 shots and turned the ball five times – had no lead to the basket. Horford, meanwhile, was able to focus on taking away drop-off passes to Embiid.

The move slowed the Sixers’ attack. Seeming unsure how to counterattack, they shot just 36% from the field and gave the Celtics a 15-3 lead. The Sixers later made up for that deficit, but their offense never recovered.

“You know, I thought the ball wasn’t moving for the first three or four periods of possession,” Sixers head coach Doc Rivers said.

“He went past every time,” added Embiid, who accumulated 26 points but was only 9 of 19 off the field and provided just one assist while also throwing the ball up four times. “So there we have to have that trust and, you know, keep moving the ball, find people and, you know, trust each other.”

Part of this will come from blocking open shots. The Sixers scored just eight of their 34 goals Thursday night, though many of them cleaned. Rivers could also counter by removing Tucker from the lineup and adding another shooter – during his post-game press conference he highlighted Georges Niang’s Game 6 performance of which he was proud – which would force Williams to either more Spending time on the sidelines or guarding Embiid. Either way, he would no longer lurk on the edge.

Meanwhile, Mazzulla is enjoying a 48-hour window to discuss his adjustments.

“Joe is learning, just like all of us,” said Smart after the win. “I know he’s been killed many times – rightly so, you know. He needs to make some adjustments. And he did.”

Yaron Weitzman is an NBA writer for FOX Sports. He is the author of “Tanking to the Top: The Philadelphia 76ers and the Boldest Trial in Professional Sports History.”.” Follow him on Twitter @YaronWeitzman.