Before this series, Grant Williams had never made more than eight 3-pointers in a game. He’d only ever cooked six before. He’d never been the leading scorer for the Boston Celtics.

All of that changed in the NBA playoffs on Sunday.

Jayson Tatum stated, “Grant won us a playoff game tonight.”

“A Game 7.”

Celtics controlled the second half in a 109-81 victory over the Milwaukee Bucks at TD Garden on Sunday, with Williams scoring a career-high 27 points and Tatum adding 23 of his own.

After blowing a 14-point fourth-quarter lead in Game 5, the Bucks took a 3-2 lead. Boston needed to win Games 6 and 7.

After pulling away late in Game 6 against Milwaukee, the Celtics used the 3-point shot in Game 7 to create some distance between themselves and the Bucks.

Celtics set a new playoff franchise mark with 22 3-pointers, and Williams tied Stephen Curry (twice) and Marcus Morris for the most 3-pointers in a Game 7 with seven.

Williams had already established a career-high of nine 3-point attempts in a game in Game 2 of this series.

In Game 7, he broke NBA’s Game 7 record for 3-point attempts, which was previously held by Curry.

In the process, he got a new nickname from Jaylen Brown.

Brown said, “Call him Grant Curry right now.”

Bucks’ defense is designed to keep opponents out of the paint and force them to shoot 3-pointers. The plan in Game 7 was to leave Williams wide open.

Bucks center Brook Lopez, who was assigned to Williams early in the game, left Williams on the wing to prevent Brown and Tatum from driving.

Brown explained, “That’s what they were giving us.”

“As a result, we had to keep passing, and he was wide open. Grant is a good shot, and we trust all of our players. He followed through.”

Williams opened the game with a 3-pointer, but he missed five of his next six shots. But his teammates and coaches continued urging him that if he was open, he should shoot it.

Ime Udoka, Celtics’ coach, stated, “I instructed him to let it go.”

“They’re showing you more contempt now than they did previously in the series. That was their strategy for him and the other guys, to shift the focus and force them to try to beat us.”

“You could see it on the first one he made. Shoot the ball, I basically said. What other options do you have? Stop crashing into people. Take the shot they’re throwing at you.”

Their remarks began to stick after they missed a few open shots in the second quarter.

“It’s difficult to focus when your entire team, like 15 people, walks up to you and tells you to keep shooting,” Williams said.

“It was just like, they’re promoting it, so why not take advantage of every opportunity?”

Williams was not drafted as a 3-point shooter in the NBA. In fact, he only made 15 three-pointers in his final season at Tennessee and only 30 in his whole collegiate career.

He shot 25% from three as a rookie but improved to 37.2 percent last year. He increased both his volume and percentage this year, shooting 41.1 percent and 3.4 per game.

Williams, on the other hand, had struggled against the Bucks after his Game 2 outburst, hitting 2-of-14 from outside the arc in his last four games.

Milwaukee opted to leave him open in Game 7 because of this. That tactic, unfortunately for the Bucks, backfired.

Tatum said, “He came up huge.”

“He was fantastic. You’ll need it in the playoffs. To be a star in their role, you need men who come off the bench.”

Celtics concluded the game with a 22-of-54 3-point shooting percentage, while the Bucks were only 4-of-32.

According to an international sports website, that’s the greatest 3-point deficit in a Game 7 in NBA history (Golden State had 21 to Oklahoma City’s 3 in Game 6 of the 2016 Western Conference finals).

Boston made 110 3-pointers in the series, the third-most in a playoff series ever, compared to Milwaukee’s 57.

According to the website, this is also the greatest 3-point disparity in a series between two teams in NBA history.

Despite his 3-point shooting, Williams may have displayed the most emotion of the night on a defensive play in the fourth quarter with the game almost won.

With Boston leading 94-73 midway through the fourth quarter, Milwaukee’s Bobby Portis received the ball in the open court, with just Williams standing between him and the basket.

Williams batted away Portis’ attempt for a slam.

As the TD Garden roared, Williams spun around and pumped his fist at the crowd.

“I was just very excited and really, really pumped when I got the block,” Williams said.

“Because you’ll have moments where it goes the other way and others where you get the block throughout your career.”

Celtics’ win on Sunday was also the first time they had overcome a 3-2 deficit to win a series since the Eastern Conference playoffs against the Atlanta Hawks in 1988.

Celtics lost in the Eastern Conference finals to the Detroit Pistons that year, a fate they hope to avoid this season.

Boston has advanced to the Eastern Conference finals four times in the last six seasons.

The previous three, including the 2020 final in Orlando, Florida, versus the Miami Heat, were all losses.

Brown was a member of the last three teams and understands that the work isn’t done yet.

“We still have a long way to go,” Brown remarked. “Prepare to go by doing everything it takes to get your mind and body in order. There are none.”

The Eastern Conference finals begin in Miami on Tuesday. It shouldn’t be debatable whether Williams will attempt 18 3s again.

Tatum had a message for Tennessee’s third-year forward before continuing to laud him.

“I warned him not to grow used to it,” Tatum explained.

More playoff basketball, on the other hand, is something Boston can get used to.