The Celtics avoided a pre-All-Star letdown Wednesday night, closing out the unofficial first half of their season with a 124-105 dismantling of the Chicago Bulls at TD Garden.

Trade-deadline pickup Nikola Vucevic tallied a 19-point, 11-rebound double-double against his former team to help Boston bounce back from Sunday’s lopsided loss to the New York Knicks.

“(He looked) much more comfortable today,” head coach Joe Mazzulla said of Vucevic, who had his first full practice with the Celtics on Tuesday. “… He values the details and wants to get it right, so he put a lot of preparation into it and was much better tonight.”

Payton Pritchard led all scorers with 25 points, eight assists and five rebounds off the bench. All-Star starter Jaylen Brown added 24-4-4 on 9-of-20 shooting, and Jordan Walsh turned in his strongest outing in weeks, finishing with 16 points on 7-of-12 shooting, six rebounds, three assists, three steals and one block.

Former Celtics guard Anfernee Simons was quiet in his return to Boston, finishing with seven points on 3-of-9 shooting and five rebounds. Simons’ trade last week — which netted the Celtics an experienced, floor-stretching big man in Vucevic — was part of a full-scale overhaul for the suddenly rebuilding Bulls.

Six of the 10 Chicago players who saw minutes Wednesday weren’t with the team when the Bulls beat the Celtics on Jan. 24, including three starters. Since that game, the Bulls have lost six straight and nine of 10, sinking to 11th in the Eastern Conference standings.

The 35-19 Celtics, meanwhile, continue to look like bona fide East contenders, even after their Super Bowl Sunday dud against New York. They head into NBA All-Star weekend with wins in five of their last six games and 10 of their last 14, owning the fourth-best record in the NBA behind Oklahoma City, Detroit and San Antonio.

Most of Boston’s roster now will be off until Feb. 19, when the team begins a four-game West Coast swing at Golden State. Two Celtics players were chosen to participate in All-Star festivities: Brown, who will start Sunday’s main event for the first time in his career, and two-way player Ron Harper Jr., who will take part in both the Rising Stars challenge and the Shooting Stars competition.

“If you take a look up to this point, I think we have a clear understanding of who we are as a team,” Mazzulla said. “From a tactical standpoint, from an identity standpoint, from a mindset standpoint, I think we played more times than not to the best version of ourselves. And I think the challenge is, can we maintain that? And can we also take it to another level?”

The Celtics went away from the double-big starting lineup they fielded in the previous three games, shifting backup center Luka Garza to the bench and replacing him with Baylor Scheierman.

It was the eighth start of the season and fourth in the last five games for Scheierman (10 points, five rebounds), who drew pregame praise from Mazzulla for his defense and rebounding.

“Statistically, I think obviously you’ve seen a big jump in his rebounding,” Mazzulla said. “But his defensive versatility — he’s guarded point guards; he’s guarded centers. He has a clear understanding of our defensive system and the adjustments to that within a game, and he can guard different guys. And offensively, same thing. He has the ability to kind of read the game in real time.”

Mazzulla continued to start Neemias Queta at center and use Vucevic off the bench. Queta suffered an apparent ankle injury midway through the first quarter that sent him to the locker room, but he later returned.

After a slow start, the Celtics took control after Mazzulla’s first round of substitutions, which inserted Vucevic, Pritchard, Harper and Hugo Gonzalez in a near-full line change. Boston, which trailed 18-17 at the time, built a nine-point lead by the end of the first quarter that ballooned to 29 in the second.

Pritchard, whom Boston moved from starter to sixth man out of necessity after trading Simons, was uber-efficient in the first half, scoring 16 points on 7-of-8 shooting with four assists. Brown added 18 first-half points, including back-to-back 3-pointers in the first quarter and consecutive driving layups in the second. Vucevic had 10 and 6 by halftime and drilled his first two threes.

“(Tuesday’s practice) helped a lot,” Vucevic said. “Finally having the time to go through stuff (in a) little more detail, more reps, that always helps. Before that, I had a walkthrough with the coaches and a shootaround, and it was just a lot at once. I think even that day in between where I was able to take time off and watch some more tape, try to learn a plays a little more, I felt like it settled a little bit better. So I think tonight was a good step forward of where we can get to. I felt a lot more comfortable out there, and I think the guys felt more comfortable around me, and we were able to build some good chemistry.”

Another first-half difference-maker: Walsh. The third-year wing’s playing time has dipped of late, but he gave Boston an impressive shift in this one. Walsh played 12 uninterrupted minutes in the first and second quarters, during which the Celtics outscored the Bulls by 25 points. He also drew one of the loudest pops from the Garden crowd when he picked Simons’ pocket near halfcourt and sprinted for a fast-break dunk.

“I think it’s just the mindset that he brings,” Mazzulla said. “I think the steal that he had at halfcourt that led to the dunk, I think a couple of the offensive rebounds that he had, it’s just coming in to make an impact right away.”

All told, the Celtics shot 58.3% overall and 52.6% from 3-point range in the first half, doubled up the Bulls on the glass (27-13) and took a 72-44 lead into halftime.

Chicago never threatened in the second half, during which the Celtics got an extended look at their newest addition. Vucevic played 26 minutes in the win to Queta’s 15 and was far more impactful than he was in his rough outing against the Knicks, when he struggled at both ends and was a minus-24.

Boston outscored Chicago by 26 points with Vucevic on the floor. He was efficient as a shooter (7-for-12; 4-for-5 from three) and held up well enough defensively, notching two blocks and one steal. Vucevic also showed his skills as a passer with three assists, including two to a cutting Walsh.

“Vuc, I love him,” Walsh said. “It’s great. Every time he catches the ball, I’m just cutting, and he’s looking every time. So it’s great. It’s a way to kind of get involved in the office without having the ball in your hands, you know? It’s super good to have a guy facilitate that and also stretch the floor and do so many things.”

Continuing to build chemistry with the 35-year-old center will be a point of emphasis for the Celtics when they reconvene next week.

The Celtics won’t return to TD Garden until Friday, Feb. 27, when they host the Brooklyn Nets to open a stretch of four home games in eight days. All eyes then will be on rehabbing superstar Jayson Tatum, whose practice with Boston’s G League team this week suggested he could be nearing a return.