Derrick White proves to be a boost in first game for Celtics as they win seventh game in a row

Derrick White was in the Spurs’ hotel in Atlanta on Thursday, getting ready for the game against the Hawks the following night, when San Antonio coach Gregg Popovich came to his room and told him that the only NBA team he had ever played for had traded him. He was a Boston Celtic now.

“It was all pretty crazy,” White said. “I was pretty shocked. I didn’t see it coming, but as soon as I got [to Boston], I got excited and just happy to come here and help the team.”

White, whose father is from the Boston area and is a longtime Celtics fan, arrived in the city Friday morning, but it was unclear whether he would be able to play against the Nuggets at TD Garden on Friday night. He had a quick game-film crash course with coach Ime Udoka — an assistant with San Antonio during White’s first two seasons there — and then about 45 minutes before tip-off, he was cleared to make his debut.

And within minutes, it seemed as if he had been there all along. White received a standing ovation when he checked in midway through the first quarter, instantly showed his value as a defender, floor spacer, and passer, and then played the game’s final 17 minutes, helping the Celtics rally for a 108-102 win over the Nuggets.

White finished with 15 points, 6 rebounds, and 2 assists. He was all smiles as he walked off the court afterward, and he signed his headband and handed it to a young fan before heading to Boston’s locker room.

“I was just trying to figure it out, try not to be in the way,” White said, “and whatever position I was in out there, just try to make the right play. So no matter what spot you’re in on the court, just try to make the right basketball play, and it comes pretty easy after that.”

The Celtics are hopeful that White, who is under contract through the 2024-25 season, can become an essential piece as the team continues to build around Jayson Tatum and Jaylen Brown. In his first appearance, he certainly did not stall the progress of this suddenly surging team.

“We don’t miss a beat with him out there,” Udoka said. “Space, defensive ability, shooting ability, simple things like running to corners and spacing — things that have been ingrained in him and been drilled, and that carried over tonight.”

Boston has won seven games in a row and nine of its last 10 to improbably catapult into the thick of the Eastern Conference playoff race. And after mostly crafting this streak against overmatched and undermanned competition, this victory over a Western Conference playoff team felt more significant.

The Celtics trailed by as many as 11 points in the game and they were behind by 7 early in the fourth quarter, but they surged back behind a closing group in which White replaced Al Horford and joined the other four regular starters.

“A couple weeks ago, months ago, early on in the season, a game like this probably would have gotten away from us,” guard Marcus Smart said. “…We didn’t let anything fluster us. We kept trusting one another.”

Smart had 22 points, 7 assists, 5 rebounds, and 5 steals, and Robert Williams added 15 points and 16 rebounds, helping offset Jayson Tatum (24 points) and Jaylen Brown combining to go 1 for 14 from the 3-point line. Nikola Jokic had 23 points, 16 rebounds, and 11 assists for Denver.

Center Daniel Theis, who was acquired in a trade with the Rockets on Thursday, was on the bench in street clothes Friday night but is expected to be available to face the Hawks on Sunday, giving the Celtics their first full look at their new-look group.

First-year president of basketball operations Brad Stevens traded away seven players Thursday, but the surging core remained intact. Now it can move forward without the possibility of a breakup looming, and it can do so with two key new pieces.

“I was glad that we were able to keep that group, especially going through what we went through at the beginning of the year,” Smart said. “We’re finally clicking. We’re finally coming together. To be able to see what we can do, I’m just glad we’re able to do that.”

The Celtics trailed, 88-81, with just over nine minutes left Friday when Smart missed a layup inside. But Horford came up with a rebound and Payton Pritchard, who had been 0 for 5, ended a scattered possession by drilling a deep 3-pointer from the right arc, igniting a 10-2 Boston run.

White, who drilled a pair of 3-pointers during his first-half stint, scored inside as he was fouled with 1:59 left to give Boston a 100-97 lead. At the other end, Denver’s Zeke Nnaji appeared to have a path to an open layup, but Williams swooped in and blocked the shot, chased down the loose ball and flipped a behind-the-back pass to Smart to preserve the lead. Smart stretched the advantage to 102-97 with a pair of free throws, and the Nuggets were never a threat again.