BOSTON -- Kyrie Irving found himself back on the Boston Celtics' famed parquet floor on Christmas Day, wearing his customary No. 11 jersey -- the same number he said he hoped would one day hang from the rafters here inside TD Garden.

Only this time, Irving wasn't playing for the Celtics. Instead, in his first game back here since leaving as a free agent last summer, he reminded Boston why it traded for him in the first place, scoring a Brooklyn Nets Christmas-record 37 points, while Kevin Durant added 29, as Brooklyn erased a halftime deficit and routed the Celtics in a 123-95 victory.

"It was nothing tactical going into the second half," said Irving, after he and Durant each scored 20 points after halftime, nearly outscoring the entire Celtics team by themselves.

"It was really up to us to make high basketball IQ plays and then be able to stop them on the defensive end."

The Nets have a ton of offensive firepower around their two stars, but the plan in the second half, more often than not, was simply to get Irving or Durant the ball and get out of the way. And to be fair, when a team has two of the best isolation scorers in the league, that's a pretty high IQ way to play.

"They're very capable of pouring it on," Celtics coach Brad Stevens said. "I think [Brooklyn is] the deepest team in the NBA and certainly is in the conversation to be the best."

While Irving and Durant chose to team up last year, it took 18 months for that partnership to materialize on the court thanks to Durant's recovery from surgery for a torn Achilles tendon. And because of shoulder issues that Irving had last season, it took just as long for him to make his official return to the place he called home for two seasons.

But the two stars more than made up for the wait with a scintillating performance, as each was able to score with the customary ease that they both separately have made their names by doing over the past decade.

With Kemba Walker, Irving's replacement at point guard here in Boston, sidelined as part of an ongoing program to strengthen his balky left knee, the Celtics were simply outgunned by the two offensive supernovas they were going up against. Irving and Durant repeatedly got their preferred shots with a calm precision that Boston, despite often playing good defense, was left powerless to stop.

That was especially the case in the second half, when Irving and Durant evenly split 40 points on 15-for-21 shooting -- including 6-for-7 from 3-point range.

Conversely, the Celtics, as a team, only scored 41 points after halftime.

"Definitely not," Celtics guard Marcus Smart said when asked if he was surprised at how good Brooklyn's stars looked. "You got two of the greatest players in the game to date. They've got some great players around them to follow. So we're not surprised; we've got to come out and be better. We have to be precise with everything we do. We have to execute to the best of our ability, because that's what they force you to do. They force you to have to be almost perfect, and you have to respect that."

Ultimately, it was the lure of that partnership that drew Irving away from Boston, and to Brooklyn, in the first place. And through two games, the Nets are thrilled with how it is progressing -- though Irving isn't satisfied with things staying as they are.

"What's there to be content about?" he asked. "What's there to be happy about? It's two games. Let's move on to the next game. Let's get ready for Charlotte. Let's go do this thing again. Let's have some fun.

"Obviously, we want this season to go in a very patient current. We don't want to rush this. I know what history looks like, and when you're a part of it, and I don't want to take any day for granted, so I'm grateful I get to share it this journey with these guys."

While Irving's final season in Boston was a tumultuous one, both he and the Celtics have publicly gone out of the way to appear to bury the hatchet. Just as he did a week ago, after Brooklyn demolished Boston in the final preseason game between the two teams, Irving had a long, friendly conversation immediately afterward with several Celtics, including assistant coach Jerome Allen, young stars Jaylen Brown and Jayson Tatum, and Smart, Walker and Daniel Theis.

And as he did after that game, when asked if playing -- and winning -- in Boston had any extra meaning, Irving instead praised his former teammates.

"I'm just grateful that we're all healthy and we're all here to be able to play the game that we love," Irving said. "Obviously, competing against those guys, competing against the coaches that I had almost a year and a half ago, like I said, I'm grateful. We're going to continue to see them; we're in the same division. So, to get us started here in Boston, nothing added."