What went wrong in the Sixers’ loss to the Celtics?

The common refrain echoed across the Philadelphia 76ers’ Media Day last month was the quest for an elite defense, specifically eyeing the league’s top spot. They’d brought in P.J. Tucker, De’Anthony Melton and Danuel House to fortify a shoddy perimeter unit. Any team with Joel Embiid anchoring the action could presumably rank quite highly in that regard. And, maybe, after a pair of runner-up finishes, Embiid would finally snag an MVP trophy for himself, though this was not a publicly stated goal of his.

After one game, a 126-117 defeat to the Boston Celtics on Tuesday, both objectives are farther away from reality than they began on Tuesday night. The Sixers enabled Boston to shoot 34-of-47 (72.3 percent) inside the arc. Jaylen Brown and Jayson Tatum combined for 70 points on 71 percent true shooting. Philadelphia’s defensive rating is 131.3.

Meanwhile, Embiid, en route to six turnovers, was flustered by the Celtics’ crisp rotations and swarming limbs, and contributed mightily to its interior scoring success with a lackluster defensive outing. He did not resemble the superstar center who’s rivaled Nikola Jokic for the last two MVP nods.

Embiid’s underwhelming performance did not bury the offense much. The Sixers still generated a 118.6 offensive rating against an excellent defense, albeit one missing weakside, freelance roamer extraordinaire, Robert Williams III. James Harden dominated, dropping 35 points (90.8 percent true shooting) and seven dimes. Tyrese Maxey added 21 points (60.6 percent true shooting). They drilled 13-of-34 (38.2 percent) of their long balls, led by Harden’s five and Tobias Harris’ three.

Embiid’s struggles inflicted the most damage defensively. He was wretched. A pair of early fouls seemingly influenced some of his decision-making, but even before then, he didn’t appear sharp or aggressive. Once the foul trouble subsided, he continued to play similarly. He was either late or absent on numerous rotations inside the paint. His pick-and-roll defense regressed to levels rarely seen throughout his career, especially throughout the last couple seasons.

Over the past few years, his regular-season defense has fluctuated — though, still generally sufficient — but not to this degree of hindrance. The Sixers may have bolstered their perimeter options, yet they still need Embiid to be quite good, regardless of whether he’s up to an All-Defensive-caliber tier. That was not the case by any stretch Tuesday. Embiid led the charge at Media Day in aiming for the NBA’s best defense. His 2022-23 debut did not reflect that sentiment.

While Embiid’s showing may have headlined and summarized Philadelphia’s problems, they extended well beyond the big fella. Ranging from screen navigation, off-ball positioning and transition efforts, Harden was atrocious, despite his offensive brilliance. He doesn’t need to be a plus defender, but the neutral-to-slight-negative impact of last year did not resonate whatsoever. Evidenced by Tatum burning him on the backcut above, his lateral quickness has declined, but the issues aren’t confined to athletic limitations.

Individual shortcomings from Philadelphia’s two stars don’t fill the scope of things either. The Sixers’ defensive communication around screens looked like a bunch of unfamiliar teammates learning on the fly against a cohesive unit full of dudes who have played a year (or many) together. They typically wanted to switch most picks, not all of them, however, and that ambiguity spurred some confusion upon which the Celtics capitalized.

Four of the nine rotation players were foreign to Sixers games before this month, so some patience to streamline these instances should be afforded. Any defensive scheme with new personnel requires time to master, let alone switching, an approach with so many moving parts that demands prompt communication to counter any openings or mistakes. Nonetheless, a litany of botched switches proved to be one of the Sixers’ downfalls amid a dismal defensive debut.

Thanks to effective nights from Harden, Maxey and Harris, who banded together for 70 points (68 percent true shooting) and nine assists, Philadelphia’s offense hummed. Embiid’s experience did not replicate his teammates’, though.

He didn’t establish menacing post position consistently; Noah Vonleh and Al Horford were tremendous about pushing him way out on his catches. Boston’s help positioning and pesky hands on his touches complicated endeavors. He settled for six triples (one make), a quota he only met in six regular-season games last year. His post-ups were clunky and precarious, regardless of whether he turned it over, which happened six times.

These hiccups — the Celtics’ elite defense and Embiid’s own quandaries — operate in tandem with poor spacing that seemed to frustrate the superstar on various occasions, when he could be seen directing traffic, yearning for the optimal alignments around him. Boston’s defense can be overwhelming as is, let alone if you simplify when and how its double-teams confront Embiid. These cuts from Harris, as well as the lack of a strongside, spot-up release valve, exacerbated matters for the low-block connoisseur.

Highlighting these plays is not intended to absolve Embiid of his offensive mistakes. Seven of his points in the fourth came with Boston holding a double-digit advantage and prioritizing defending threes over twos. 26 points on 59 percent true shooting overstates his offensive imprint. But there were external factors, ones donning Philadelphia red and blue rather than solely Boston green and gold, that compounded the difficulties.

Head coach Doc Rivers has long stressed the delicate nature and importance of proper spacing around Embiid, who’s offered similar comments. The spacing did not amplify him Tuesday and is one of many aspects this group must rectify to become the type of team they wish to be by April.