NEW YORK >> Feeling he was close to a deal for Paul Pierce, a thought crossed Billy King’s mind.

“I asked, ‘What about KG?”” the Nets general manager said.

Yes, Brooklyn is also getting Kevin Garnett — and a real shot at contending for a championship.

“I would say ending today it’s a good day for the organization,” King said Friday on a conference call.

And it’s the close of a championship chapter in the Celtics’ storied history.

Boston’s blockbuster breakup is complete. Pierce and Garnett are Brooklyn-bound, and it’s the Nets who are thinking big as they head into their second season in their new home.

“Today, the basketball gods smiled on the Nets,” team owner Mikhail Prokhorov said in a statement. “With the arrival of Kevin Garnett and Paul Pierce, we have achieved a great balance on our roster between veteran stars and young talents. This team will be dazzling to watch, and tough to compete against.”

It’s a nine-player, three-draft-pick swap agreed to on draft night and centered on the two aging champions who won a title in Boston in 2008. Celtics general manager Danny Ainge eventually agreed to put Garnett in the deal, and Garnett waved his no-trade clause after some lobbying from new Nets coach Jason Kidd and point guard Deron Williams.

The Nets also got Jason Terry and D.J. White from Boston, while sending Gerald Wallace, Kris Humphries, MarShon Brooks, Kris Joseph, Keith Bogans and first-round draft picks in 2014, 2016 and 2018 to the rebuilding Celtics. Boston also gets the right to swap first-round picks in 2017.

The teams agreed to the deal on June 27 but it couldn’t be completed until after next season’s salary cap was set. The Nets plan to introduce their new stars Thursday at Barclays Center.

Boston won five straight division titles from 2008-12 before falling back last season, the first following Ray Allen’s departure to Miami. Then the Celtics let coach Doc Rivers out of his contract after the season by acquiring a first-round pick from the Los Angeles Clippers. This trade signals a new phase for the team that has won an NBA-high 17 championships and got used to being in the hunt again after Garnett arrived in 2007.

“Paul and Kevin exemplified everything it means to be a Celtic,” Celtics managing partner and CEO Wyc Grousbeck said. “They were instrumental in bringing back Celtic Pride and providing our fans with the franchise’s first championship in over 20 years in 2008. We wish them nothing but the best in the future.”

The Nets went 49-33 in their first season in Brooklyn and have spent big in hopes of bettering that in 2013-14. They also signed versatile forward Andrei Kirilenko, re-signed backup big man Andray Blatche and added reserve guard Shaun Livingston.

They blew well past the luxury tax line and are facing a bill of $80 million in taxes, but Prokhorov wanted a title within five years of owning the team. A starting five of Garnett, Pierce, Williams, Joe Johnson and Brook Lopez, along with former Sixth Man of the Year Terry, has a chance to compete for one.

The window to win is small, two years at the most given the ages of Pierce and Garnett — though King sees those as incentive more than detriment.

“I enjoy the fact that people keep questioning Kevin Garnett and Paul Pierce because I know that they’ll come out and prove people wrong,” King said.

The Celtics hadn’t won a title since 1986 before they acquired Garnett and Allen in 2007. They joined with Pierce to form the core of a team that won 66 games and a title their first season together, reached the NBA Finals again in 2010, and returned the Celtics to their longtime place atop the league.

But Garnett is 37, Pierce will be 36 by opening night, and Ainge realized the Celtics’ days of competing for titles with this group were finished after a first-round exit, and chose to go in another direction.

“We would not have won Banner 17 without Paul and Kevin and they will go down amongst the all-time great players to have ever worn a Celtics uniform,” Ainge said. “At the same time we are excited to welcome Gerald, Kris, Keith, MarShon and Kris to the Celtics family. They bring a wealth of talent, experience, depth, and flexibility to our team.”

The Celtics thanked Garnett and Pierce, who is second on the team’s career scoring list, with a full-page ad in Friday’s Boston Globe.

Wallace was a starter for the Nets last season, and Humphries and Bogans sometimes started. They join a Celtics team led by first-year coach Brad Stevens, the former Butler coach who was hired to replace Rivers.

The Nets also will be led by a rookie in Kidd, who was hired shortly after retiring as a player and will see much more talent when he looks down his bench.

Garnett is a 15-time All-Star and Pierce a 10-time selection, and both are among the NBA’s top-20 career scorers. Even while slowing down a bit as they near the end of their careers, Pierce averaged 18.6 points last season, and Garnett added 14.8 points and 7.8 rebounds while remaining one of the NBA’s most tenacious defensive big men.

Terry averaged 13.5 points last season, his only one in Boston.

Kirilenko agreed to his contract Thursday and was signed Friday. He will make $3.2 million this season and has an option for the second year. The forward opted out of a deal that would have paid him $10 million in Minnesota this season and will play again for former CSKA Moscow boss Prokhorov.

“He is a true talent with tremendous versatility,” Prokhorov said. “As a fellow countryman, I am especially proud that the best Russian player in the history of the NBA will be wearing a Nets jersey.”