Celtics run away from Heat, 104-84, to seize series lead, and other Game 3 observations

MIAMI — As angst around the Celtics swelled after the Heat evened this Eastern Conference first-round playoff series at 1-all, the Celtics themselves sounded both confident and unconcerned. Yes, their 3-point defense had some holes in the Game 2 loss, but they believed the fix was simple.

And on Saturday night, the Celtics left no room for error. They extended their defense, swarmed shooters, and did more than enough to roll to a 104-84 win that gave them a 2-1 lead in this best-of-seven. It was Boston’s second wire-to-wire win of the series.

Jaylen Brown and Jayson Tatum had 22 points apiece to lead the Celtics. Kristaps Porzingis bounced back from a tough Game 2 and had 18 points. Bam Adebayo had 20 points and 9 rebounds for Miami, which was held to just 12 points in the opening quarter and could never recover.

One game after Miami went 23 for 43 from the 3-point line in its surprising win at TD Garden, it made just 9 of 27 at home.

Observations from Saturday:

⋅ It did not take long for Porzingis to wipe away his forgettable 1-for-9 shooting performance in Game 2. He scored Boston’s first 8 points in Game 3 by draining a pair of 3-pointers and converting an alley-oop from Jrue Holiday. Porzingis’s start was stalled midway through the quarter when he had to go to the bench after picking up his second foul, but the early flurry seemed important for him, and it also helped the Celtics grab a lead that they never relinquished. By the time Porzingis returned three minutes into the second, the lead had expanded to 17.

⋅ By surging to the early lead, the Celtics erased any momentum the Heat may have hoped to bring home from their upset win Wednesday at TD Garden. Miami started 1 for 13 from the field with a turnover, and everything was a chore.

It was clear from the start that the Celtics were focused on ramping up their defensive pressure. They had success with a full-court press when the Heat inbounded on dead-ball situations under the Celtics’ hoop, either forcing turnovers or simply sparking an uncomfortable start to a possession. And once the Heat settled into their halfcourt offense, the Celtics deployed their smothering, switching defense that extended beyond the 3-point line. In Game 2, Boston often dared Miami’s below-average shooters to fire away from long range. In this game, the Celtics took no chances. The Heat were 4 for 14 from beyond the arc in the first half. The 28.6 percent shooting is notable, but so is the fact that the Celtics significantly reduced Miami’s attempt rate. The Heat took 22 2-pointers in the first half.

⋅ Tyler Herro, who carved up Boston as a scorer and distributor in Game 2, had a particularly tough time at the start of this one. He was held scoreless until he hit a runner in the lane with eight minutes left in the second quarter and did not register an assist in the first half.

⋅ Even though their offense was abysmal during a 12-point first quarter, the Heat were still very much in the game, trailing by 9. It felt as if Boston might have missed a chance to really surge. But then the Celtics poured in three 3-pointers over the first 90 seconds of the second, with Tatum hitting a pair and Sam Hauser adding one. The lead did not dip below double digits again.

⋅ The Celtics led by as many as 25 points in the first half despite not really getting any spectacular individual performances. They had balance, and multiple players took over the game for segments. Derrick White’s came near the end of the second quarter. He poured in 12 points over a stretch of less than four minutes, with the most spectacular basket coming when he soared into the lane after Brown missed a free throw, caught the carom in midair and converted a layup. It was slightly reminiscent of his indelible buzzer-beating putback that won Game 6 of the conference finals here last year.

⋅ When the ball goes out of bounds off of the opposing team, Al Horford often pleads with officials to give him the ball quickly so the Celtics can start a fast break before the opponent can set its defense. The officials are usually in no hurry, and opponents are usually capable of setting up. But Horford had a rare hit in the third quarter Saturday. Miami’s Caleb Martin went tumbling into the crowd after trying to save a loose ball. Horford sprinted into place and urged the referee to give him the ball, and the Celtics capitalized on the one-man advantage by getting a Brown layup at the other end.

Adam Himmelsbach can be reached at adam.himmelsbach@globe.com. Follow him @adamhimmelsbach.