These Celtics could have beaten the Heat, but they lacked the killer instinct — and that doomed them

Bam Adebayo keeps Jaylen Brown away from the ball on Sunday night.Kevin C. Cox/Getty

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ORLANDO — As the Celtics reflected on their blown opportunity, their chance to reach the NBA Finals as the highest seed left in the Eastern Conference, Glenn Frey’s “The Heat is On” blared through the cozy AdventHealth Arena as the Miami Heat celebrated their return to elite status.

The Celtics could have been on the floor celebrating, drowning in confetti and sharing deep hugs, but they just weren’t tough enough. They lacked the killer instinct. They panicked in crunch time. They were exposed for their lack of a true center.

They just weren’t good enough.

The Celtics will, however long this offseason lasts, lament this series. They gave away the first two games — or rather they were taken away from them — and when they needed to be perfect, they weren’t.

Miami had too many shooters. Too much Bam Adebayo and the Celtics were exposed for the talented-but-flawed team they are. The 125-113 loss in Game 6 on Sunday was a microcosm of the series. When the Celtics played better than Miami, they won. But when the games were even, when it came down to the final minutes, they were no match.

It was a painful way to end what could have been a special season. Reaching the Eastern Conference finals for the third time in four years was an admirable achievement but losing in six games to the fifth seed, a team very few picked to even reach the conference finals, force the Celtics to leave the NBA bubble with their pride bruised, realizing next year will really be next year (2021).

Daniel Theis tried his best to tie up Miami's Bam Adebayo (13).Mark J. Terrill/Associated Press

Miami outscored the Celtics, 35-17, after falling behind by 6 points with 9:15 left. The Celtics just couldn’t contain Adebayo, the new-age big man who played point center and dribbled repeatedly into the paint and scored. The Celtics have been trying to get away with Daniel Theis as a starting center all season, a position they really never addressed fully after Al Horford left and Aron Baynes was traded.

Theis tried vigorously to match Adebayo but lost nearly every matchup. With Adebayo able to get into the paint and score at will and Miami spreading the floor with shooters, the Celtics just couldn’t get defensive stops.

They lacked toughness, even though none of the players who spoke with the media after the game said it was an issue. The most definitive sign of panic for this team is to resort to 3-pointers. The Celtics took 14 in the final period, missing 12.

Jayson Tatum, as brilliant as he is for 22 years old, couldn’t come to the rescue. Jaylen Brown, as usual, didn’t get enough shots. Kemba Walker, exposed in this series for his defensive deficiencies, missed five 3-pointers in the final period. The collapse was thunderous. The Celtics ran out of counter moves.

“Best thing we did, the best stretch of defense we had all night, maybe the only good stretch of defense, was when we were switching with Grant (Williams),” a rather resigned coach Brad Stevens said. “But that got taken and exposed a little bit as well there toward the end of it. Miami deserves a lot of credit. They’re super physical, super tough, very, very savvy. I think they’re the best team in the East and deserve to be representing the East in the way that they have played.”

But who saw this coming? The road to the Finals was supposed to be clear after the Celtics beat the defending champion Toronto Raptors in seven games. But the Celtics had definitive weaknesses that were revealed by masterful Heat coach Erik Spoelstra, although what’s most disappointing is that the Celtics were out-worked and out-gritted in all four losses.

When it came to crunch time, they melted. The most talented team doesn’t always win, as we know. Sometimes it’s the team that plays better together when the game is on the line. The Celtics appeared confused about who was going to take key shots, which led to pressing. Walker trying to endear himself to teammates with a big 3, Tatum trying to show the world he’s an All-NBA player with a crafty move, Smart still trying to prove he’s a respectable 3-point shooter.

And none of those players were quite good enough in this series. Gordon Hayward was supposed to make a difference but he was hardly 100 percent, and that affected the Celtics' approach. According to an NBA source, Hayward sustained nerve and retinaculum damage in that sprained ankle and he could barely jump. He needed about two-plus more weeks of rehab that the Celtics just didn’t have. So he played on one leg.

Gordon Hayward (left) wasn't healthy enough to be of much help to the Celtics in the series.Mark J. Terrill/Associated Press

The Celtics were just hoping to push this series to seven games, hoping they had enough fortitude to make Miami nervous in a winner-take-all final game. But the lack of execution was miserable. Down, 103-102, with 5:40 left, the Celtics went 0-for-6 shooting with two turnovers over the next 3:21.

Miami scored 13 points in that stretch. It’s pretty simple why the Celtics lost. They don’t yet have the clutch gene.

“I think for us it’s more whenever we have leads learning how to maintain it, learning how to be better, not playing in spurts,” Walker said. “I thought we did that a lot throughout the course of this season. We’ll get better. We had a lot of times where all of us didn’t play together — injuries, things of that nature. This is our first year together, so we’re going to have some time to grow. It’s going to be a fun group for the next couple years.”

It’s frustrating for the Celtics to already employ the “we’ll get em next year” approach so soon after such a disheartening loss. But maybe this just wasn’t Boston’s year, but it definitely could have been and maybe should have been.

“I believe in this group; I think we were capable,” Tatum said. “We had more than enough to get the job done. We just let a couple slip away. Got to give credit to them. They played great. But I really loved and enjoyed playing on this team.”