The Celtics weren’t designed to quit like this

That might sound hyperbolic or melodramatic given that Boston is one of the final four teams left standing and that it is competing in its fifth Eastern Conference finals in the past seven years. Of course, there are plenty of other teams with gnarly wounds, including the Philadelphia 76ers, Milwaukee Bucks and Phoenix Suns, to name three aspiring contenders who quickly fired their accomplished coaches once they were eliminated.

Yet Boston, which trails the Miami Heat 3-0, appears to be an unlikely candidate to become the first team in NBA history to win a playoff series after losing the first three games. If the Celtics can’t buck history, their pain will cut deepest because of how carefully their roster was built, how successful they have been for years and how close they came to winning a title last season. Boston has followed a sound blueprint by building its nucleus through the draft, making savvy moves to address areas of need and staying patient through playoff shortcomings. Now, with a homegrown core all grown up, the Celtics are suddenly left to wonder if they will ever get to enjoy their long-awaited championship payoff.

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The Heat obliterated the Celtics in Sunday’s Game 3, running off a 128-102 blowout victory in a game the oddsmakers had expected Boston to win. Though Las Vegas looked foolish in hindsight, its confidence in Boston was understandable. The Celtics, already down 0-2 in the series, were the more desperate team. Their stars had yet to play to their standard, and they had displayed an annoying knack for flirting with disaster before pulling it together. Remember, the Celtics should have swept the Atlanta Hawks but needed six games to advance out of the first round. Then, Boston took seven games to knock out Philadelphia in the conference semifinals, when only five games should have been required given Joel Embiid’s shaky health and unimpressive play.

Miami has a better coach and a better superstar than Boston’s previous opponents, and Erik Spoelstra and Jimmy Butler have made the Celtics pay for their bad habits and shortcomings. The East finals have been a ruthless dissection; Butler broke Boston’s will with a late flourish in Game 2, and Spoelstra has coaxed far better effort and focus than Joe Mazzulla, the Celtics’ rookie coach.

Boston’s showing in Game 3 was a cross between a whoopee cushion and a bowl of soggy cereal. Jayson Tatum arrived for the biggest game of the season wearing a white suit, and then he and co-star Jaylen Brown proceeded to play like living, breathing white flags.

“I just didn’t have them ready to play,” Mazzulla said. “I’ve got to make sure when we step on that floor that we’re ready to execute, we’re ready to be physical and we’re ready to play harder than the other team.”

Surrender was in the air midway through the second quarter, and things got so ugly after halftime that Mazzulla didn’t even play most of his starters in the fourth quarter. Tatum was nearly invisible with 14 points on 18 shots; Brown was even worse, careening his way to 12 points on 17 shots.

What makes this no-show hurt worst of all is that Tatum and Brown have graduated out of the learning stage. Both are in their mid-20s, both earned all-NBA recognition this season, and both have played in at least 90 playoff games, including logging heavy minutes in last year’s Finals. They absolutely should be better than this.

“I don’t even know where to start,” Brown said. “An obvious letdown. I feel like we let our fan base and organization down, we let ourselves down, and it was collective. We could point fingers, but in reality it was just embarrassing.”

Tatum, in particular, has risen to the occasion in key moments, including a 46-point game facing elimination against the Milwaukee Bucks in last year’s second round and a 51-point Game 7 effort against the Philadelphia 76ers last week. Recently, the four-time all-star even declared himself, “Humbly, one of the best basketball players in the world.”

Yet that self-assuredness has evaporated against Butler, just as it did against the Golden State Warriors last year. So eager to be crowned, Tatum keeps tripping over his feet whenever he gets close to the throne, following up his most impressive performances with inexplicable ones.

“We’ve got to have some pride and bounce back [in Game 4],” Tatum said. “It’s unfortunate. We obviously wanted to perform better, play better, have a different outcome and at least give ourselves a chance. It’s tough. For whatever reason, we didn’t have it tonight. At this point of the season, you don’t want to say that, but that’s on us.”

The partnership between Tatum and Brown has evolved through several chapters, and they remain one of the league’s top duos on paper. Against Miami, though, they have been unable to make each other better on offense and haven’t lived up to their reputation for versatile and fierce defense.

While Mazzulla bears some responsibility for Boston’s disjointed play, a team’s most talented players are supposed to serve as its leaders, especially during a crisis. Neither has fulfilled that task against Miami, and former coach Ime Udoka, who was let go after becoming embroiled in an inappropriate relationship with a co-worker, is no longer around to push them to greater heights.

Few young stars have had it better than Tatum and Brown, who play for a prestige franchise with committed owners, excellent front-office executives and, until this season, well-regarded coaches. Former Celtics president Danny Ainge drafted Marcus Smart and Robert Williams, while Ainge’s successor, Brad Stevens, deftly landed Al Horford, Derrick White and Malcolm Brogdon in trades. What’s more, the Celtics avoided financially overcommitting to Kyrie Irving, Isaiah Thomas and Gordon Hayward, thereby maintaining crucial flexibility around their developing centerpieces.

Since drafting Brown in 2016, the Celtics have won 349 games, placing them second to the Bucks in a top five that also includes the Toronto Raptors, Denver Nuggets and Warriors. That’s precisely why Boston now feels like a victim of its own success: Toronto won the 2019 title, Milwaukee won in 2021, Golden State won in 2017, 2018 and 2022, and Denver, which holds a 3-0 lead over the Los Angeles Lakers in the Western Conference finals, could easily win this year. By that captivating and unforgiving benchmark, the Celtics have been the odd men out.

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Boston has long preferred minor course corrections over hard offseason pivots, and it has so far resisted years of rumors suggesting that Tatum and Brown should be split up. They waited out Irving’s 2019 implosion, a hard-fought loss to the Heat in the East finals, an injury-plagued 2020-21 campaign and last year’s Finals collapse against the Warriors, responding to each hurdle with faith that better days were ahead.

But the Game 3 blowout begged for a fundamental reevaluation of that hope. The 36-year-old Horford, so effective against Embiid, has looked too slow to keep up with Bam Adebayo. Smart still doesn’t shoot well enough to justify his liberal shot selection or to function effectively as a point guard, and Brogdon turned in 18 scoreless minutes when Boston desperately needed anything off the bench. Mazzulla has had no answers for Spoelstra, and he didn’t have his team engaged with its season hanging by a thread.

Despite all those issues, Tatum and Brown sit at the root of the Celtics’ problems. Boston’s roster was painstakingly fashioned with intensity, two-way impact and resilience in mind. There would be no shame in losing if their stars missed too many three-pointers or couldn’t quite match Butler’s clutch heroics. But the Celtics weren’t designed to quit like this.