Celtics' history-making Game 1 loss to Sixers highlights a glaring weakness

Celtics' history-making Game 1 loss highlights a notable weakness originally appeared on NBC Sports Boston

BOSTON -- The Celtics found another way into the record books Monday night, and not in a good way.

Boston came out firing in Game 1 of their second-round series against the Philadelphia 76ers at TD Garden, hitting 17 of their first 20 shots while taking a double-digit first half lead. But the Joel Embiid-less Sixers hung around, getting timely buckets from James Harden and capitalizing on Celtics turnovers to erase that deficit and tie the score entering the fourth quarter.

That's when Harden took over, scoring 15 of his game-high 45 points in the final frame to will Philly to a 119-115 road victory. Not only was the loss demoralizing for a Celtics team that entered as 10.5-point favorites, it also was the first of its kind in the shot clock era.

Boston is the first team in NBA history to shoot 55 percent or better (58.7 percent) while committing 10 or fewer fouls and still lose. So, what precipitated this bizarre statistical anomaly?

While the Celtics' 16 turnovers didn't help their cause, the primary culprit was Boston's defense -- particularly its plan to contain Harden.

Celtics Talk POSTGAME POD: Harden's 45-point night stuns Celtics as Embiid-less Sixers take Game 1 | Listen & Subscribe

In the first half, the Celtics tried switching on Harden and occasionally threw double-teams at the Sixers star to try to disrupt his rhythm. But Harden made Boston pay, tallying four assists in the first two quarters -- including two to DeAnthony Melton, who hit 5-of-5 3-pointers in the first half -- while adding 21 points.

In the second half, the C's deployed more 1-on-1 coverage -- and Harden responded by taking over offensively. The 33-year-old went off for 15 of Philly's 32 points in the fourth quarter and hit a dagger 3-pointer over Al Horford in single coverage to seal the Sixers' victory.

Boston's uneven defensive approach against Harden didn't sit well with Celtics guard Malcolm Brogdon, who believed his team sent too much help on Harden.

"You've got to pick your poison," Brogdon said after the game. "With them, they wanted (Jayson) Tatum to score. They let him play 1-on-1 most of the night. For us, I thought we doubled Harden a little bit too much, and it cost us.

"It puts us in long closeouts. It puts us in scramble mode. They've got a lot of shooters on the floor. They surround him with shooters, because he's a great passer."

It seems counterintuitive to let Harden go off in single coverage, but the Celtics have deployed this strategy on Embiid in the past with positive results: Philly is 3-9 against Boston when Embiid attempts 20 or more shots.

If you ask Brogdon, the Celtics need to focus on containing Sixers role players like Tyrese Maxey, Tobias Harris and Melton, who scored 26, 18 and 17 points Monday night, respectively.

"You've got to cut off the water somewhere," Brogdon said. " ... If James Harden is going to have his 45, then that'll be that. But the role guys can't have really good games as well."

Brogdon declined to single out head coach Joe Mazzulla for his team's defensive strategy, noting that players often made reads on the court without Mazzulla's input. But it's clear where Mazzulla needs his team to improve the most.

The Celtics are averaging 120.3 points per game this postseason (second behind only the Miami Heat) and have eliminated many of the offensive woes that plagued them in the 2022 playoffs. On the other end, however, they're allowing 116.3 points per game, 12th among 16 playoff teams and a far cry from their 102 points per game allowed last postseason.

If Embiid can suit up for Game 2, that Mazzulla and his staff will have some decisions to make regarding how much help they send on the star big man and Harden. But the bottom line is that Boston needs to rediscover the defensive prowess that carried the team to the NBA Finals last postseason if it wants to make a similar run this spring.