At the momenthoisted up her "Heave at Haas" on Sunday at California, Oregon's freshman guard had attempted 37 shots in two games back from injury. Eight had connected.Upon release, Ionescu's three-pointer at the buzzer, with the score 66-66, didn't appear destined to drop. It was thrown at the rim as much as shot, and Ionescu's legs kicked out awkwardly in front of her. But drop it did – thanks not to perfect shooting form, but sheer force of will.In the coming years, Ionescu will become a more polished player under UO coachand his staff. She'll get bigger in Oregon's strength program, and savvier through experience in the nation's toughest women's basketball conference.But Ionescu is blessed with a competitive spirit that already sets her apart from most of her peers. It fuels her work ethic in practice, her credibility as a leader, and her confidence in moments like Sunday.The Oregon women entered their winter break having gone 10-2 in nonconference play. The Ducks' practices after Christmas, Graves said, were uninspired; not coincidentally, Ionescu missed them while dealing with a hand injury. They then opened Pac-12 play by being swept at home by UW and WSU.But the Ducks had a new energy in practice last week, which culminated in the upset at Cal; not coincidentally, Ionescu rejoined the team for the Bay Area trip. She leads the Ducks on the road again this week, beginning at USC on Friday (8 p.m., Pac-12 Network)."Honestly, I think she's the most competitive person, in general, that I've ever seen," Eddy Ionescu, Sabrina's twin brother, said Sunday in Berkeley. "I've never seen somebody want to work so hard – and not just in basketball. She just wants to win in everything."It was appropriate that Eddy was in the stands to watch his sister's game-winner Sunday. So too their parents, and the twins' older brother, Andrei.Sabrina's shooting numbers – 5-of-20 at Cal – reflected the lingering effects of the hand injury. But her tenacity resulted in eight rebounds, and her will to win was illustrated on the game-winning shot. And nobody is more responsible for instilling those qualities in Ionescu than her family.Sabrina and Eddy were all of about 4 years old when they began playing basketball to emulate Andrei, nine years their senior. The family home had a regulation hoop and also what Sabrina called "the baby hoop." Even as small kids, the twins wanted to use the big hoop. Because Andrei used the big hoop."She always wanted to be competitive with the boys," said Dan Ionescu, the family patriarch. "Having one nine years older than you, and a twin brother, the boys stuck together, and she always wanted to compete against them. And keep in mind, we're talking about competitive in everything."Andrei stressed the importance of academics, and to this day Sabrina will call and update him on her progress in the classroom. She compared grades with Eddy as well; the twins would even compete to see which could put away clean dishes the quickest.Dan Ionescu owns a car service, and when the twins were old enough, he'd drop them off at Larkey Park in their hometown of Walnut Creek, Calif., before making a run to chauffeur a client. By the time their father circled back to pick them up several hours later, one of the twins was probably nursing a wound – usually to their pride, and often worse."We spent all day in the park playing one-on-one, 'knockout,' three-pointing shooting, everything," Eddy recalled. "Those were rough. We would go at it.""We would literally play until one of us got hurt or there was blood somewhere – or I won," Sabrina said. "Because I wouldn't stop until I won. We'd just keep going."Around middle school, Eddy experienced a growth spurt, on his way to 6-foot-4, six inches taller than his twin sister. Still they battled at Larkey Park. If Eddy needed a point, he'd back his sister down in the post, and score. She'd call him out on abusing his height advantage. But she never quit."I've never once heard Sabrina say, 'Tone it down a notch, you're playing too rough with me,'" Eddy said.In seventh grade, Sabrina was treated for stress fractures in both legs. For about six weeks, she sported hard casts on both feet. The trips to the park continued. Jump shots became set shots, the only concession to the injuries."I'd get looks from everyone," she said. "But I'd still shoot around.""Our mother (Liliana Blaj) will tell her to relax sometimes, and she won't do it," Andrei said. "She gets into that mindset and you can just see. She doesn't have that 'relax' mentality. She's about, attack.""Sometimes I feel like, if I enjoyed winning as much as I hate losing, I'd be happier," Sabrina said. "We win more than we lose, but it gets annoying sometimes because you're never really satisfied. But it's the price I pay for being so competitive."Sabrina's coach at Miramonte High School and also with the Cal Stars AAU team, Kelly Sopak, saw both the upside and the downside to Sabrina's competitive spirit."We couldn't do any team bonding games that revolved around competition," said Sopak, who sat behind Oregon's bench Friday at Stanford, and courtside Sunday at Cal. "She couldn't stand losing."On the other hand, in the summer of 2015, Sabrina passed up the chance to play for the U.S. national team — she'd won gold medals with Team USA the two previous summers — in order to play for a championship with Cal Stars. The club had lost in its championship game in 2013, and struggled in 2014 after Sabrina joined the club mid-summer after playing with Team USA. Determined to win a title for Sopak and Cal Stars, Ionescu didn't even bother trying out for Team USA in 2015."I was really dedicated to him, and to my team," Sabrina said. "So I took a chance, and I stayed." The chance paid off — Cal Stars lost just once all summer, on the way to the Nike EYBL national championship.One of Sabrina's teammates on that run was. The two have been reunited this season as freshmen at Oregon.McGwire thus saw the difference in the Ducks' practices two weeks ago, while Sabrina was still sidelined, and then last week when she returned. Those around Ionescu say she has a way of encouraging teammates to match her competitive fire."It makes me want to work harder for her," McGwire said. "I know she's doing everything in her power to get better, and it makes me want to do the same."When Ionescu made her return to action with the Ducks last week at Stanford, her impact was felt immediately. Oregon's first basket was made possible by an Ionescu offensive rebound; her 6.7 rebounds rank second on the team, and usually are accumulated through sheer effort. The Ducks' next two field goals were McGwire baskets assisted by Ionescu, and Sabrina scored herself for Oregon's fourth field goal.On the next trip down the court, Ionescu fired up a three-pointer that ended up being an airball, and she had a missed jumper and a turnover on the ensuing two possessions. The shooting futility continued for much of the night — she finished 4-of-18 at Stanford — and then into Sunday's game at California, in which she was 4-of-19 entering the last sequence.Sunday's matchup with Cal was a one-possession game for most of the fourth quarter. With about two minutes left, Ionescu said, she had a premonition she'd be in position to hit a game-winning shot, something she'd never done before in her playing career. She'd hit free throws to win games — and also, as a freshman at Miramonte, missed potential game-winning free throws, something she thinks about to this day every time she shoots free throws in practice, she said.But she'd never hit a buzzer-beater to win. Until Sunday."I had so much adrenalin, I wasn't even nervous," Ionescu recalled. "I think I might have been more nervous if we'd put in a set play or something. But I just looked at Maite (Cazorla), told her where I was going, caught it, shot it — weirdly — and it went in."As she continues to hone her skills in the coming years, at Oregon and beyond, Ionescu's shooting technique will improve. She can become a better on-ball defender, too, coaches say.But she's already proven that her will to win is second to none. It was on display for the "Heave at Haas," and will continue to help Ionescu exploit every last bit of talent she was blessed with."I think about 80 percent (of her success) is the work she puts in," Dan Ionescu said. "Yeah, she has some talent, definitely. That's primarily her vision, and her understanding of the game. But hard work is what got her where she is, and will carry her on. And she knows that."