NEW YORK -- Boston Celtics center Kristaps Porzingis scored 24 points in 32 minutes Saturday night in a 115-113 win over the Brooklyn Nets at Barclays Center, ending an eight-game absence because of an illness.

"It was extremely, extremely frustrating, just not knowing what I had," said Porzingis, who added it was an upper respiratory illness that 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 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 couldn't figure out what was wrong.

"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 saw people questioning his absence and said he sent the social media message Monday to set the record straight.

"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 was really nice. I always appreciate the love and support I get from Celtics fans and back home and everywhere."

Porzingis said that he had tried to ramp up for games, including last Saturday's showdown in Boston against the Los Angeles Lakers, but would "crash" and run out of energy. Last Saturday morning, he said he was so tired that he couldn't get out of bed for shootaround before the Lakers game.

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

On Saturday, he was upgraded to probable before the game and was officially cleared by the Celtics (49-19) about 90 minutes before tip-off against the 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 tie with the Philadelphia 76ers.

Porzingis played 32 minutes -- including almost the entire fourth quarter -- and didn't look like he had missed time, finishing a team-best plus-13 while also grabbing two rebounds and blocking a shot.

"It just shows the skill set he has," said Celtics guard Payton Pritchard, who broke former Heat guard Wayne Ellington's NBA record for 3-pointers off the bench in a season. "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 quirks of Boston's season has been its record with Porzingis sidelined (28-7) compared with him on the court (21-12 after Saturday's victory). No one, however, would argue that the Celtics are better without the 7-foot-3 sharpshooter's combination of rim protection and versatile scoring.

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

Boston is now 17-4 in its past 21 games and 5 games ahead of the New York Knicks for second place in the Eastern Conference.

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 up things. One of those goals will be getting Boston's preferred starting lineup of Porzingis, Jayson Tatum, Jaylen Brown, Jrue Holiday and Derrick White humming. That group outscored opponents by 11 points per 100 possessions last season, but has been outscored in its 20 games this season.

Boston, however, isn't concerned about that.

"We know what we can do when everybody's out there," said Tatum, who had 20 points, 8 rebounds and 8 assists.

After a long two-plus weeks, Porzingis was happy to be with his teammates and hopes he has 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."