‘That’s who we are’: The Celtics couldn’t be rattled and knew when to pounce — and that’s how they beat the Warriors in Game 1

SAN FRANCISCO — There were times during Game 1 of the NBA Finals Thursday night when the Warriors did everything the world has come to know them for during their dynastic run.

They were constantly on the move, spraying 3-pointers, and making the Celtics’ elite defense look like it was running on a bed of banana peels. The first run came at the start, when Stephen Curry turned back the clock and did as he pleased. The second came in the third quarter, when the Warriors devoured Boston and pushed to a 12-point lead.

But very little rattles these Celtics. Not big deficits. Not raucous crowds. Not even a miserable shooting night by their superstar. In this case, they did just enough to stay within reach, and then in the fourth quarter, they pounced.

Boston started the period by connecting on seven 3-pointers in a row, with the Chase Center crowd’s mood transitioning from indifference to uneasiness to stunned silence.

The Celtics quickly flipped a double-digit fourth-quarter deficit into a double-digit lead, a monumental swing under any circumstance, much less the grandest stage in all of basketball. Twelve minutes after raising early questions about whether they were ready for this big moment, they walked off the court with a commanding, statement-making 120-108 win.

“We continue to fight,” guard Marcus Smart said. “That’s who we are.”

In a blink, Boston has ripped homecourt advantage away from the Warriors, though it continues to be unclear whether that even matters. The Celtics are now 8-2 on the road in these playoffs.

Miami had been undefeated at home entering the Eastern Conference finals until the Celtics rolled into their building and won three of four games. The Warriors had been undefeated at home in these playoffs, until the Celtics stomped in and made it clear that precedent does not matter to them.

“The road,” guard Derrick White said, “is the time where it’s just us.”

After Thursday’s win the Celtics were pleased, but hardly doing cartwheels.

Team co-owner Wyc Grousbeck stood 15 feet from the podium and watched the end of coach Ime Udoka’s press conference. When Udoka finished and walked out, Grousbeck gave him a subtle nod and fist-pound.

Jayson Tatum pointed out that Boston lost its opening game in its previous two series and advanced both times anyway. The message was that this game was important, but more important ones will follow.

Jayson Tatum didn't make the biggest impact when it comes to the box score.Matthew J Lee/Globe staff

Still, the Warriors have to be somewhat disturbed by the fact that they lost by 12 points on a night when Tatum, a first-team All-NBA choice, made just 3 of 17 shots. Tatum sprayed timely passes and registered 13 assists, and he was picked up by some superb long-range shooting.

Al Horford (26 points), Derrick White (21) and Smart (18)—nary a 40-percent long-range shooter in that group—combined to make 15 of 23 3-pointers. Afterward, Warriors forward Draymond Green mostly dismissed that flurry as an aberration and insisted it would not happen again.

And while there was certainly luck involved, the Warriors also made a decision to dare all three to connect, leaving each plenty of space to try. That approach might have to be amended now, and that could open other avenues for players such as Tatum. The All-Star forward shrugged off his grisly shooting night.

“I don’t expect to shoot that bad again,” he said. “But if it means we keep winning, I’ll take it.”

In the first quarter Tatum air-balled a shot by about two feet and also missed two free throws. This Celtics group was playing its first ever Finals game, on the road against a team that has made this round its playground, and it felt like it.

“I think everybody had nerves today from our side,” guard Payton Pritchard said.

Curry, meanwhile, was dancing and dashing as if he had never left this stage. He hit a Finals-record six first-quarter 3-pointers and poured in 21 points. It was quite an introduction for the Celtics to stomach.

Still, they regrouped, held Curry scoreless in the second quarter and clawed to a 56-54 halftime lead. Golden State has been dominant in third quarters this season, though, and used a 38-24 run sparked by six 3-pointers and 11 second-chance points to take a 12-point lead to the fourth.

“We had a lot of time left, right?” Tatum said. “It wasn’t time to hang your head or be done; it was time to figure it out.”

With Curry on the bench, Brown hit a jumper and a 3-pointer before finding Robert Williams for a dunk. Warriors coach Steve Kerr called timeout to get Curry back into the game, but it didn’t matter. Brown hit a layup and another 3-pointer, an essential flurry with Tatum scuffling.

“I feel like if you put the ball in my hands, more often than not I’m going to put ourselves in a good position to win,” Brown said.

With Golden State clinging to a 103-100 lead, the Celtics erupted for a game-defining 17-0 run that included five 3-pointers. The last two came from Smart, whose questionable shot selection at the end of Game 7 against the Heat nearly led to a collapse.

On this night, though, it was the capper of a late rout, with the Celtics fans spread out among this Pacific Coast crowd finally making their voices heard.

Al Horford greets the Celtics' bench after scoring 2 of his 11 fourth-quarter points.Matthew J Lee/Globe staff

‘That’s who we are’: The Celtics couldn’t be rattled and knew when to pounce — and that’s how they beat the Warriors in Game 1

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