The Bulls’ biggest X-factor might not be on the roster.

But she likely was instrumental in helping the team extend its season and get one step closer to the playoffs Wednesday night.

Viewers watching the broadcast of the Bulls’ 109-105 comeback win over the Raptors in the play-in tournament could hear a fan screaming loudly every time a member of the Raptors took a free throw.

The audible screech initially garnered confusion, as the Raptors were at home in front of their own fans.

But the screams were quickly identified as belonging to Bulls star DeMar DeRozan’s daughter, who was sitting in the lower section behind the basket at Scotiabank Arena.

The broadcast subsequently showed DeRozan’s daughter, Diar, waiting for Raptors players to begin their shooting motion from the free-throw line and promptly unleashing a high-pitched howl.

It certainly worked.

And now, the Raptors are left to hear the sound ringing in their nightmares throughout their newly-started offseason.

Toronto shot a paltry 50 percent from the free-throw line, going 18 of 36 in the loss.

And after losing by just four points, and blowing a 19-point third-quarter lead, those 18 missed free throws, including six in the fourth quarter, proved pivotal.

It was also the second-most missed free throws in a game this season.

The Raptors owned a 78.4 percent collective free-throw percentage in the regular season, a whopping 28.4 percent better than what they mustered with Diar DeRozan in their ears.

“She went viral,” DeRozan told reporters after the game before laughing. “I haven’t let it soak in yet. Everybody keeps saying that’s her, I kept hearing something during the game. Then there was one free throw, somebody missed, and I looked back and I was like ‘damn, that’s my daughter screaming?’ I was just making sure she was alright.”

DeRozan nearly prevented his daughter’s effort, however.

But in the highest-stakes game of the year so far, a little hooky was allowed.

“My daughter called me the other day when she was getting out of school,” DeRozan said. “And she just said ‘dad can I come to the Toronto game.’ I remember her coming to all the Toronto games when she was a kid. I almost said no because she’s in school back home. She kept asking, she was adamant about coming to support.

“And I just said ‘alright, you can miss one day of school and come to a game.’ And I’m glad I did, I owe her some money, for sure.”

DeRozan spent the first nine seasons of his career with the Raptors.

The Bulls, who entered the play-in tournament as the No. 9 seed in the Eastern Conference, next face the Heat, who entered as the No. 7 seed, with a playoff spot on the line.

The winner of that matchup will claim the No. 8 seed and the final spot in the playoffs in the Eastern Conference.

But the Bulls will have to manage without their newfound star.

Diar will be back in school, DeRozan said after the game.

It was the first time the Raptors have blown a 19-point lead since Nov. 14, 2018 in a loss to the Pistons, a streak spanning 1,610 days according to ESPN Stats and Info.

Lavine led the comeback with 39 points, and DeRozan poured in 23 points as well.