Boston went nearly two decades without a championship title in professional sports before the Patriots broke the drought.

Bill Belichick not only changed football culture across the region forever but he brought back the sweet taste of winning to New England. He built a fraternity with head coaches of Boston’s other major sports teams, and success followed.

Since the turn of the century, the Patriots, Celtics, Bruins and Red Sox have combined to win 12 championships, the most in any city across the country.

Though it’s been five years since the Patriots defeated the Rams in Super Bowl LIII, it’s still a far cry from the 16-year drought between the Celtics winning the NBA Finals in 1986 and Belichick’s first ring in 2001.

Imitating the signature Belichick look, Joe Mazzulla cut off the sleeves of a gray Celtics sweatshirt ahead of Thursday night’s game in Milwaukee. He told reporters he admired the former Patriots coach’s sense of humor and “his ability to make connections through different sports.”

In pursuit of his first NBA title, the Celtics coach attended Patriots training camp last summer and talked with Belichick about “two-for-ones and pressing defenses.” Mazzulla said Belichick’s attention to detail amazed him.

“I’m thankful for the relationship that he and I have built, gotten to learn from him, gotten to talk to him,” Mazzulla said. “When you see guys who go through coaching changes or slumps 1) it is easy to forget how hard it is to be a coach, 2) it’s easy to take for granted long-term success, and 3) we’re normal guys that have a job and try to do the best job that we can.”

Bruins head coach Jim Montgomery said he also took a lot out of his interactions with Belichick. Before Thursday’s game in Las Vegas, he highlighted how he’d always ask the Patriots coach questions as he tried to “soak in (his) knowledge.”

Montgomery called Belichick an “open book” on how to handle different situations and treat role players and star players and the importance of owning the middle of the field and ice.

“I know he has impacted a lot of football coaches,” Montgomery said, “but I think it goes across every sport because you study other coaches and how they handle players, the team and the differences between the motivational and structure Xs and Os so to speak.”

“Obviously he’s a master at it all and someone I am very lucky to have spent time with,” the Bruins coach added.

In the midst of the 2021 MLB playoffs, Belichick sent a text message to Red Sox manager Alex Cora after the ballclub defeated the Yankees in a wild-card matchup. Cora called the message “more personal”  than when he met the Patriots coach after winning the 2018 World Series.

“That’s like the highlight of the year,” Cora gushed. “I got the text from this random area code. That’s cool, to be honest with you, for somebody of his status to wish us luck.”

The Associated Press contributed to this report

New England Patriots head coach Bill Belichick and his former girlfriend Linda Holliday with Dave Dombrowski, ex-President of Baseball Operations for the Boston Red Sox, during the fourth inning of the game against the New York Yankees at Fenway Park on August 5, 2018. (Herald file photo)