Gianna Gregoire got out of her wheelchair and walked.

It had been six weeks since her last steps. And on this day, her feet gripped the Madison Square Garden hardwood, as they had done many times before.

“A place like that is one in a million,” Gregoire said between bites of ice cream and french fries at a Morris Park diner. “Center of the world. Center of New York City. I wanted my first steps to be in the center of what’s important. And what’s important is the Knicks.”

The 20-year-old suffered a severe stroke on Oct. 14 and 11 days later was diagnosed with glioblastoma, a rare and aggressive brain cancer. Days later, she awoke with Knicks great Allan Houston at her bedside and a desire to walk her first post-stroke steps at the Garden.

The embattled franchise has always brought joy to Gregoire.

With the help of the organization and her half-brother Anthony Donahue — who’s been “connected with the Knicks for 20 years” and developed relationships with people in the organization — Gregoire’s wish to grace the Garden court again came to fruition before a Dec. 1 game against the Celtics.

It’s not the first time someone in her family has leaned on the team.

Donahue, who spoke to The Post clad in a Yankees cap and gold Knicks medallion necklace, saw his first Knicks game at 10 years old. He still keeps that ticket stub: April 2, 1994, versus the Heat. Then and now, the Knicks have given him a welcome distraction from life’s tougher moments.

Gianna Gregoire Anthony Donahue
Gregoire and Donahue met with The Post in early 2020 at the Golden Eagle restaurant in the Bronx.Jake Nisse

“No matter what I was going through when I was a kid, if I was going to visit the city, and I was supposed to see my mom but she’s canceling on me because she was doped up on heroin, there was a Knicks game that night,” the 36-year-old told The Post.

Donahue, who was largely raised by his grandparents, hardly knew his parents growing up. His mom was a drug addict, and his dad was out of the picture until he was 17. But he found solace in the Knicks.

“I could just think about John Starks, or Latrell Sprewell or Patrick Ewing,” Donahue said. “And in my world, it made everything better.”

It’s the second time his half-sister Gregoire has battled brain cancer in her lifetime, having previously beaten the disease after being diagnosed in 2010.

This battle has provided a unique set of challenges, as she is fighting the disease and recovering from her stroke at the same time. Gregoire has already undergone radiation treatment and resumed chemotherapy (in pill form) last week. Donahue tweeted on Jan. 24 that her cancer was “shrinking,” according to an MRI exam done earlier that week.

Her stroke has rendered the left side of her body paralyzed and confined her to a wheelchair, though she is beginning to regain the ability to walk while she fights the cancer. After months of living at the United Hebrew of New Rochelle rehab center, she briefly returned home last week, but another stroke suffered on Sunday means she will again be living in hospitals for now.

The Knicks’ support has remained a constant in her tumultuous life.

Back in 2012, as detailed in The Post, Gregoire celebrated her clean bill of health by meeting various Knicks — including Jeremy Lin and Amar’e Stoudemire — after her brother’s #WinForGianna hashtag caught the attention of the team. Donahue previously hosted a Knicks show on SNY and currently works with the team hosting fan events.

So it was only fitting that the Knicks would play a role in Gregoire’s most recent fight with cancer. After her meeting with Houston, she got words of encouragement from Carmelo Anthony over FaceTime. Mike Breen also spoke with her during that Dec. 1 trip to the Garden — a place she usually visits 10 to 15 times per season.

“Melo told me to keep my head up, keep fighting, keep going the way I am and I’ll get to where I need to be,” she said of the former Knicks star, who has since signed with the Blazers.

Donahue and Gregoire view the organization as family.

“Allan [Houston] will call me after games just to pray,” said Donahue, who’s not particularly religious.

Gregoire and Donahue, who share a mother, have always been close. They have a far different relationship than most siblings.

Like Donahue, Gregoire’s parents were not really in the picture growing up. Her father left when she was a baby and her mother, who has been clean for 10 years, is only sporadically involved in her life. It’s her big brother Anthony who takes her to doctor’s appointments, supports her financially and puts a smile on her face when she needs it most.

Donahue says that his half-sister’s insurance covers most of her treatment, but the costs still add up. The Iron Matt foundation, which financially supports families affected by brain cancer, helps ease Donahue’s economic burden; miscellaneous charges like hospital parking and eating out take a toll. The two have repaid that generosity by holding a toy drive for the foundation the past seven years. Donahue also sells wristbands sporting the #WinForGianna message on his social media platforms for $10 apiece to help fund Gregoire’s fight.

“I wanted my first steps to be in the center of what’s important. And what’s important is the Knicks.”

Not all the support they receive, though, is financial. Gregoire sees the hundreds of well-wishing replies to Donahue’s social media updates of her progress. She takes comfort in her postgame text messages with Donahue (who goes to virtually every home game). And she notices the extra stops that the Knicks pull out for her, like when they put her and her brother up in a suite during that Celtics game.

Donahue will often bring the salty popcorn from the Delta Lounge to her. His friend even gifted Gregoire a literal piece of the Knicks’ court, which rested by her hospital bed. Donahue and his half-sister would also watch away games together at the rehab center. The constant reminders of the team distract her, yet also give her a tangible goal.

“We’re planning [on going to] future games. I want to go to more games. I don’t wanna just wheel into a game, I wanna walk into a game,” she said.

Donahue wants the same for her, but his perspective extends far beyond going to basketball games. He views her everyday existence — which currently includes texting with one hand and a recently shaved head — as a massive inspiration.

And that’s reflected in how they view the scope of her battle with brain cancer, something an estimated 23,820 people were diagnosed with in 2019, according to the National Cancer Institute. People with no interest in the Knicks stumble upon Donahue’s social media updates on his sister every day. One man messaged him recently to tell him his “selfish” mood that day was changed by watching a video of Gregoire’s fight.

Knicks Gianna Gregoire
A piece of the Knicks is (literally) always with Gregoire.Twitter

Gregoire has spoken about her fight to kids with cancer and at Houston’s basketball camp as well. She’s eager to connect with more survivors, and hopes to be able to knit crochets in the near future. You’d never tell from her attitude that she is fighting a truly brutal disease.

“She’s happier than everybody probably reading this article,” her brother said.

Her cancer is draining, ruthless, scary. The future is uncertain and the road to recovery will be long and painful.

But there’s one place that can assuage that pain, if only for a couple of hours.

“I can be myself with no hair at the Garden and not a feel a thing.”