SABRINA IONESCU COULDN'T wait for the start of the NBA season. Specifically, the WNBA All-Star circled the Boston Celtics' season opener as appointment viewing, brimming with excitement about Jrue Holiday's debut with his new franchise.

Ionescu, the 26-year-old sharpshooter who grew up in the Bay Area and stars for the New York Liberty, isn't a Celtics fan and has never met Holiday. But she has a personal connection with the two-time All-Star guard: Holiday was the first NBA player to wear her Nike signature shoe, the Sabrina 1s, in game action.

Holiday had worn Sabrina 1s during media day and preseason games, but it was a milestone moment for Ionescu to watch Holiday in a player-exclusive white, black and blue colorway during Boston's Oct. 17 win against the New York Knicks.

"I don't even think I watched the game," Ionescu told ESPN. "I was really just watching his feet."

Holiday, who boasts a career-best 43.5% mark from 3-point range this season, has worn Sabrina 1s in 53 games, the most of any player in the league. "Maybe that's part of the reason why I'm shooting so well," he told ESPN.

Over the course of the 2023-24 season, 77 NBA players have joined Holiday in wearing the Sabrina 1s, according to on-court sneaker tracker kixstats.com. While Holiday chose to wear Sabrina 1s in large part because he thought it'd be a "cool" way to show support for women's sports -- an especially meaningful matter to the husband of National Soccer Hall of Famer Lauren Holiday -- several players told ESPN they haven't given gender a second thought when taking the court in them.

That was the goal when Ionescu and Nike first teamed up on her debut sneaker that launched in September. And with players praising their looks, familiar feel and functionality, the Sabrina 1s have become a popular addition to lockers around the league -- next to Nike staples such as Kobes and LeBrons.

"Not a women's basketball shoe or a men's basketball shoe, but just basketball," Ionescu said of the Sabrina 1s.

"Being able to tell that story and have people authentically buy in and respect that, I think the time is now in terms of wanting that to be pushed."

A DOZEN PLAYERS across the WNBA's 27-year history have gotten signature shoe deals, starting with Sheryl Swoopes' Nike deal that began in 1995 and spanned seven years. Rebecca Lobo (Reebok), Nikki McCray (Fila), Candace Parker (Adidas) and Breanna Stewart (Puma) are among those who followed. Elena Delle Donne, who has a Nike deal, joins Stewart and Ionescu as active WNBA players with signature shoe deals.

None have had such crossover into the NBA as Ionescu's Nikes.

Knicks guard Jalen Brunson wore a white-and-orange colorway while scoring a then-career-high 50 points on Dec. 15. Indiana Pacers guard Tyrese Haliburton sported a cornucopia-esque custom colorway -- red, orange, green and yellow on the right shoe with black, red and blue on the left -- that suited the style of the Pacers' 157-152 win over the Atlanta Hawks on Nov. 21.

Detroit Pistons guard Cade Cunningham went with a simpler customized version during a 30-point, 12-assist outing when the Pistons snapped their historic losing streak on Dec. 30 -- all white with a red swoosh on the right shoe and a blue one on the left.

And the Sabrina 1s have built a reach beyond NBA and WNBA courts. They've been spotted regularly in the men's and women's NCAA tournaments this season. Ionescu personally gifted pairs to Caitlin Clark, the superstar likely destined for her own signature shoe deal, and her Iowa teammates this week before the Hawkeyes' Final Four appearance.

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The sneakers have also made it overseas. American-born Fenerbahce forward Nigel Hayes-Davis wore them while breaking the EuroLeague single-game scoring record with 50 points on March 29.

The shoes feature a vertically slanted swoosh on the arched side of the foot, which represents breaking barriers, something Ionescu is used to doing.

She was the first player in NCAA history, man or woman, to have 2,000 points and 1,000 combined rebounds and assists in a career. Last season, she broke Diana Taurasi's 17-year record for most 3-pointers in a WNBA season. And most recently she took on Golden State Warriors star Stephen Curry in a 3-point duel during NBA All-Star Weekend in February.

"The W is going to have the most success it's ever had in this upcoming year," Haliburton, who sponsors a girls' elite youth basketball program in his native Wisconsin, told ESPN. "I think as allies of those players and the league in general, we should do our part to show love when we can."

And for Haliburton and other players around the league, it doesn't hurt that Ionescu's debut sneaker reminds them of one of the most popular and sought-after signature shoes in league history.

"I don't remember," Haliburton said, "the last time a woman's shoe has been popping the way this has."

MANY NBA PLAYERS who have frequently worn Sabrina 1s this season have compared them to another player's signature Nike shoe: Kobe Bryant's.

"The silhouette and feel of them kind of feel like an old Kobe," Utah Jazz guard Jordan Clarkson told ESPN. "They're super comfortable. The design is nice."

As Dallas Mavericks rookie center Dereck Lively II told ESPN, "They remind me of Kobes, but at the same time she has her own twist to it."

The resemblance isn't a coincidence. Ionescu, the No. 1 overall pick in the 2020 WNBA draft out of Oregon, wore Bryant's Kobe Vs in most of her pro games before getting her own signature shoe. Ionescu worked closely with Nike designers during the development process to include her favorite elements of the Kobes.

"It was really important for us to take that inspiration and take the insights from her favorites and deliver it in a way that was truly uniquely Sabrina's," Nike footwear product director Deepa Ramprasad told ESPN. "I think that kind of lineage is absolutely something that was intentional in the inception of the shoe, and we believe we've delivered something that's very uniquely hers."

The shoes include aesthetic nods to Ionescu's heritage, such as an intricate embroidery on the forefront and through the eyelets inspired by Romanian art and architecture.

"As far as looks go, I think they're one of the best shoes in the league," Denver Nuggets guard Christian Braun told ESPN. Braun has worked them into his game rotation along with his Kobes.

The fashion aspect is significant, as are the personal touches -- a stylized "S" in a circle on the tongue and a lowercase "i" on the heel that also features her signature -- but Ionescu is proudest of the functional quality of her signature shoe.

"I think what was really important to me was understanding what was helping me on the court," Ionescu said. "I played in Kobes professionally, but then in college I was actually in Hyperdunks and wore almost every signature athlete. So I was really able to tell what I needed from a performance standpoint, and being able to have free rein to create whatever it is I wanted in a performance shoe was really most exciting."

Ionescu emphasized her desire to maximize quickness while reducing fatigue as the top priorities for the shoe, a combination that Ramprasad compared to "trying to combine oil and vinegar."

From the numbers of NBA players who wear them to their testimonials, Nike and Ionescu pulled it off. Players rave about the sleek Sabrina 1s feeling light but cushioned.

"It's an all-around comfortable, amazing shoe," Nuggets shooting guard Kentavious Caldwell-Pope told ESPN. "Just the grip and all the stuff on it, it's a great shoe for sure."

NIKE SELLS NINE standard colorways of the Sabrina 1s, also offering the option to customize. That has unlocked a bit of nostalgia for some players.

"When we were all in middle school, we definitely were making Kobes and LeBrons -- shoes we would never buy, but we always would just make them on the computer," said Haliburton, who wore a two-tone pink pair of Sabrina 1s on Wednesday night against the Brooklyn Nets.

"So it's pretty cool that [with] Sabrinas, you have the ability to do that. ... You see people making their own creations, putting their numbers on them. That takes us back to our childhood."

Nuggets rookie Julian Strawther created seven or eight customized colorways.

"They came out fire," Strawther told ESPN. "She put out a heater with her first shoe, so I gotta ride."

Clarkson, who said he recognizes how the Sabrina 1s' impact might benefit someone like his daughter, estimated that he has created at least 15 of his own colorways: "I've got a whole locker full."

Fashion has been a significant factor in the Sabrina 1s' popularity throughout the NBA. It's also a reflection of the immense respect NBA players have for the women's game, which is in the midst of major growth, due in large part to the emergence of marketable stars in the WNBA and NCAA.

But ultimately, NBA players appreciate a great basketball shoe.

"It's funny that people are like, 'Why are you wearing a girl's shoe?'" Lively said. "I'm like, 'Why wouldn't I?'"

ESPN's Tim Bontemps contributed to this report.