As they faced their first test of adversity, Kristaps Porzingis was curious to see how the Celtics responded. They had dropped two winnable games in a row after looking like world beaters in the first five games.

After Wednesday’s loss to the 76ers, Porzingis said he even liked adversity. As these new-look Celtics look to develop chemistry with each other, their response was an important building block, even if it’s still early November.

It was what they were looking for. The Nets, even without leading scorer Cam Thomas, gave the Celtics all they could handle again, just six days after they did so in Brooklyn. But the Celtics, once again, had every response. Jaylen Brown scored 28 points on five 3-pointers in a big bounce-back effort, Jayson Tatum added 23, Jrue Holiday nearly had a triple-double with 13 points, 12 rebounds and nine assists, and the bench stepped up with big contributions as the Celtics pulled away from the feisty Nets for a 121-107 victory at TD Garden.

The Celtics won their first In-Season Tournament game decisively and have three more to go in group play, with the next tournament game coming next week in Toronto.

Without Thomas and several other players out for the Nets, the Celtics faced another smaller lineup. But they barely needed Kristaps Porzingis, who had just nine points on four shots. Tatum wasn’t even a huge factor. But they rode Brown, who was hot early. The Celtics held a commanding lead for most of the night but the Nets never went away with their 3-point shooting.

The Celtics, though, after a bad shooting night in Philadelphia, had more than enough firepower from downtown on Friday. They went 19-for-52 from deep, which included five each from Brown and Sam Hauser and four from Tatum as they easily held off Brooklyn.

The Nets, trailing by double digits for most of the third quarter, cut it to single digits heading into the fourth quarter. But the Celtics’ bench – including Hauser, Payton Pritchard and Luke Kornet – went on an 11-2 run to begin the final period as Pritchard found Hauser for a pair of 3-pointers to put the Nets away.

Some takeaways from the victory:

– Brown submitted a forgettable performance in Wednesday’s loss to the 76ers despite igniting a late comeback bid that fell short, but responded right away on Friday. An offensive rebound from Tatum in the early going led to a three-point for Brown, who seemed to feel more confident with every shot. On the next possession, Brown hit a 3-pointer in transition, and the ball kept finding him. Brown scored 12 points – more than he did all of Wednesday – in the first seven minutes on his way to 21 points in the first half.

– Pritchard has had a rough start to the season. He had gone scoreless in four of the previous five games as he continues to get adjusted to a bigger role he wanted off the bench. But if he was pressing a little, the guard could breathe some after Friday’s performance.

Pritchard came off the bench late in the first quarter and proceeded to play in the final 16 minutes of the first half, as he continued to make positive plays for the Celtics. He was instrumental in a critical response from the Celtics bench after the Nets went on a 9-0 run to tie the game at 27 by drilling a triple – his first points since Nov. 1’s blowout against the Pacers – as he led the bench on a strong stretch. Moments later, Pritchard missed a 3-pointer but rebounded it before relocating to the corner and making a 3-pointer as the Celtics went on an 8-0 run.

Pritchard didn’t score the rest of the half but played the entirety of the second as he made impact plays like grabbing a steal and corralling rebounds. When he returned late in the third quarter, the Celtics’ lead had dwindled to nine when Pritchard was fouled. He made a free throw, misfired on the second but he rebounded his own miss and laid it in to restore Boston’s lead to 12.

– In another example of how lethal the Celtics’ offense is, neither Porzingis or Tatum had made a big scoring impact as Brown took over and Boston took an early lead anyway. Porzingis took just three shots in the first half because he was in some early foul trouble. Tatum, delegating to Brown had zero points midway through the second period before he scored 13 in the matter of three minutes.