NEW YORK — Boston Celtics center Kristaps Porzingis scored 24 points in 32 minutes Saturday in a 115-113 win over the Brooklyn Nets at Barclays Center, ending an 8-game stint on the sidelines with an illness.

“It was extremely, extremely frustrating, just not knowing what I had,” Porzingis said afterward, adding that it was an upper respiratory illness that eventually developed into something like bronchitis or mononucleosis. “But I haven’t been this sick for probably ever in my life. So I was really, for a week really just laying at home trying to recover. And after that I had lingering fatigue — and I still have it a little bit — but at least I’m not getting into shape to be able to play.

“But after each workout I was, boom, big crash. I was really, really fatigued. Like, not normal. So, yeah, it’s taking a little bit longer, but I’m doing everything, all my bio-hacking stuff that I know, and just trying to get back in the best shape possible.”

The 7-foot-3 Latvian had been out since a Feb. 26 loss to the Detroit Pistons with what the team had only described as a non-COVID illness. During Monday’s win over the Utah Jazz in Boston, however, Porzingis posted on social media that he and the team had been unable to figure out what was wrong with him.

“I have been dealing with some viral illness that we haven’t been able to fully identify yet,” Porzingis wrote. “I am recovering and getting better. But still working my way back to full [strength] to help this team. Thanks for the support and [I’m] hoping for a healthy return soon.”

Porzingis had seen questions surrounding why he’d continued to be out because of an illness and said he sent the message out on social media Monday in order to set the record straight about why he’d been sidelined, and to explain that it had to be a real issue for him to be missing so much time.

“I was just getting a lot of questions,” he said. “I saw it on social media and people wanted to know what’s going on, why I’m out for so long. Honestly it was frustrating for me. I was like, ‘Illness, out. Illness, out.’ Like, ‘Come on, this guy can’t play through some illness?’ Even I would think that.

“I just wanted to let people know that I was really, like, dealing with something. I’d never sit out for some cough or something. If I’m out with illness, it has to be where I really can’t play to help the team. That was it. I just wanted to give an update and that’s it. I got a lot of support that. That was really nice. I always appreciate the love and support I get from Celtics fans and back home and everywhere.”

Porzingis said that he’d repeatedly tried to ramp up for games, including last Saturday’s showdown in Boston against the Los Angeles Lakers, only to then “crash” and run out of energy. Last Saturday morning, he said he was so tired he couldn’t get out of bed for shootaround ahead of the Laker game, causing him to sit out once again.

But Porzingis had been upgraded to questionable for both Wednesday’s loss to the Oklahoma City Thunder and Friday’s win over the Miami Heat — including going through morning shootaround workouts ahead of both of them — before ultimately being ruled out.

Saturday, though, he was upgraded to probable in the hours leading up to the game and was officially made available by the Celtics (49-19) about 90 minutes before tip-off against the tanking Nets (22-45). Brooklyn lost for the 10th time in 11 games to move back into sole possession of the fifth spot in the NBA’s Draft Lottery, breaking a momentary tie with the Philadelphia 76ers.

Porzingis went on to play 32 minutes — including almost the entire fourth quarter — and didn’t look like he’d missed any time at all, finishing a team-best plus-13 while also grabbing a couple rebounds and blocking a shot.

“It just shows the skillset he has,” said Celtics guard Payton Pritchard, who became the NBA’s all-time record holder for 3-pointers off the bench Saturday, passing former Miami Heat guard Wayne Ellington. “I mean, he’s a unicorn, so he’s an unreal player and obviously when we have him we’re just even more dangerous.”

One of the weird quirks of Boston’s season has been that the Celitcs have been significantly better with Porzingis sidelined (28-7) than with him on the court (21-12 after Saturday’s victory). No one, however, would argue that the Celtics are better off without the 7-foot-3 sharpshooter’s combination of rim protection defensively and versatile scoring ability offensively.

Porzingis missed the first month of the season following offseason surgery to repair a rare tendon injury in his left leg, an injury he suffered during Boston’s five-game NBA Finals victory over the Dallas Mavericks.

Boston’s victory Saturday improved the team to 17-4 across its last 21 games. The Celtics are now a full 5.5 games clear of the New York Knicks for second place in the Eastern Conference pending the result of New York’s showdown with the Golden State Warriors later Saturday night in San Francisco.

Given the Celtics are also nine losses behind the Cleveland Cavaliers for the top spot in the Eastern Conference, the final few weeks of the regular season will be about fine tuning and cleaning things up. One of those will be getting Boston’s preferred starting lineup of Porzingis, Jayson Tatum, Jaylen Brown, Jrue Holiday and Derrick White humming – a group that outscored opponents by 11 points per 100 possessions last season, but has been outscored in the 20 games it has been deployed in so far this season.

Boston, however, isn’t concerned about that.

“We know what we can do,” said Jayson Tatum, who had 20 points, 8 rebounds and 8 assists. “When everybody’s out there.”

And Porzingis, after a long two-and-half weeks, was just happy to be back out there with his teammates again and hopes that he’s put this illness behind him for good.

“It felt great,” he said. “Honestly, I was not feeling perfect today, either, but I got in the mindset of, ‘I want to play and start to get back.’

“As the game went on, I felt better and better. I kind of had a little crash in the third but I pushed through it and in the fourth had a great fourth. Yeah, it was a close one, but I’m happy we got it done.”