NBA playoffs 2022: Jimmy Butler, Al Horford and the tense final seconds of Game 7 between the Boston Celtics and Miami Heat

MIAMI -- Erik Spoelstra's eyes traced the shot as it left Jimmy Butler's hands. The arc looked good. It was rotating perfectly. The emotions swelled in the Miami Heat coach's chest as he instinctively kicked out his legs in the final moments of Sunday's Game 7 of the Eastern Conference finals inside FTX Arena.

"I thought for sure it was going down," Spoelstra said. "I thought it would have been an incredible storyline for Jimmy to pull up and hit that 3."

"I was like, man, what the hell," Boston Celtics guard Jaylen Brown said.

"Oh," Celtics coach Ime Udoka said, "he's been making big shots all series."

"Not again," thought Marcus Smart, who watched Butler nail a clutch shot over him at the end of Game 6.

Butler posed as the ball approached the rim; the nearby Heat bench coiled for a collective leap. But Butler had played 47 minutes, 45 seconds of a 48-minute game, two days after he played for 47 minutes in Boston. Maybe it was fatigue, maybe it was the lingering soreness in his knee, maybe it was the pressure, but the ball ended up hitting the front of the rim.

The storyline Spoelstra was dreaming about? The Heat -- battered, bruised and frankly undermanned in a physical series -- had pulled a magic act to even get to Sunday's contest. Looking at the past two weeks fairly, this was a tied series only because of the Heat's mix of guile, timing and anti-inflammatories. And Miami was doing it again in Game 7.

Seven times the Celtics had built their lead to double figures, and seven times the Heat clawed back. Had Butler's 3-pointer dropped with 15 seconds to play, the Heat would have taken a one-point lead -- their first of the game.

The Heat had a puncher's chance, an underdog with nothing to lose who can take a wild risk. One perfect swing at the right moment could knock out the favorite.

Butler could've driven the ball to the rim and gone for the tie. He had momentum and space, having started his own fast break after grabbing a rebound. And Butler is one of the league's best finishers around the rim, his strength and dexterity perfect for scoring in traffic.

Instead, with himself and his team tired and hurting, Butler went for the haymaker.

"My thought process was, 'Go for the win,' which I did," said Butler, who backed up his 47 points in Game 6 with 35 in Game 7. "[I] missed a shot. But I'm taking that shot. My teammates liked the shot that I took. So I'm living with it."

Butler isn't a man of regrets, but the miss will sting. A few moments later, the Celtics polished off the 100-96 victory to earn their first trip to the NBA Finals in 12 years with a series against the Golden State Warriors.

This is where the other side of the storyline comes in. And that is the man who came out to stop Butler.

The Celtics were on the verge of a devastating defeat, blowing a vital series in one of the worst ways imaginable. But if there was one player they could have picked to be in front of a streaking Butler in that moment, it was Al Horford.

Horford did everything right. He got out in front of Butler and "loaded" -- jargon for setting himself to defend against a player on a drive -- with Horford between the Heat star and the basket.

"I didn't know what he was going to do," said Horford, who was playing with a heavy heart after the death of his maternal grandfather earlier in the week. "It seemed like he was going to go for the shot, but I had to make sure that I stayed solid; and when he pulled up for the 3, I was like, let me contest the best way that I can. He got a good look at it."

Horford is the best defender the Celtics have when it comes to contesting shots like the one Butler was about to attempt. Horford contested 29 more shots than any other Celtic in the series because he's always in the right spot.

When Butler went against Horford in the series, he shot 27%. When the Milwaukee Bucks' Giannis Antetokounmpo went against Horford in the East semifinal round, he made 37%. Earlier in Sunday's game, Horford absolutely stoned the Heat's Max Strus on a dunk attempt in a classic example of his ability even at age 35.

The math behind Butler's 3-point attempt screamed "bad shot." Butler, who isn't a 3-point shooter by nature, took just 19 pull-up 3-pointers for the entire season and made just six. But in this series, he was 4-of-7 on open 3s. This one felt open. For a second, it was wide-open.

"It was nerve-wracking," Horford said of Butler's shot. "He pulled up and anything could have happened there."

It was the 141st playoff game of Horford's 15-year career and he'd never been to the Finals, the longest streak in the history of the NBA. And had he been a little slower to pivot and rush out to bother Butler, maybe that streak would still be alive.

As the contest ended, Horford chucked the game ball into the air. When the Bob Cousy Trophy was awarded to the Celtics as the East's champions, it was handed to Horford.

For all of Butler and the Heat's disappointment, Horford and his team's joy was the balance -- and the latest chapter in what has already been a rugged playoff ride.

"This journey is not easy. We had a hard path," Horford said. "Brooklyn, Milwaukee -- the defending champs -- and Miami ... they took us to the brink. For our group, it's resiliency, it's switching the page, moving on to the next thing, and we did that all season."