In an Australian Open that has been defined by stunning upsets and fast-rising young stars, Danielle Collins is getting her moment in the sun.

To call Collins the surprise of the women’s draw would be an understatement. As far as paths to Grand Slam semifinals go, that of the 25-year-old Floridian who won two NCAA singles championships at Virginia is twisty and unusual.

For one, Collins graduated from college, a rarity in tennis, especially on the women’s side. She considers herself self-taught, having grown up playing on public courts in St. Petersburg, Fla., not in an academy designed to mold pros. And as an unseeded entry in tennis’s first major of the year, she won for the first time in the main draw of a Grand Slam just last Sunday, when she took down No. 14 seed Julia Goerges in three sets.

Her career record in Grand Slam matches before that was 0-5. Three victories over seeded players later, Collins has a date with two-time Wimbledon champion Petra Kvitova in Wednesday’s semifinals.

“This has all been a really incredible experience,” Collins told reporters in Melbourne after her 2-6, 7-5, 6-1 victory over Anastasia Pavlyuchenkova in the quarterfinals. “Obviously, it's my first time playing main draw here in Australia, so I think that's a little bit new to me. This time last year I was playing a challenger in Newport Beach.”

It hasn’t just been Collins’s power and go-for-broke hitting that has fueled her run to the semifinals. Fiery, feisty confidence has been the hallmark of her play throughout the major perhaps more than any one shot.

Keeping that emotion in check is something the 35th-ranked player in the world has long worked on, said Mark Guilbeau, the former Virginia coach who worked with Collins when she won the NCAA singles tournament in 2014 as a sophomore and 2016 as a senior. Against Pavlyuchenkova, Collins emitted teeth-baring screams and double fist-pumps after big games, thwacked her racket against the court and pulled faces after dubious line calls.

Her signature moment of the tournament came in a 55-minute, 6-0, 6-2 victory over the three-time Grand Slam champion Angelique Kerber in what was perhaps the most impressive upset of the tournament aside from Stefanos Tsitsipas’s win over Roger Federer.

In the second point of the second set, Kerber celebrated a forehand winner with a run-of-the-mill “Come on!”

When Collins claimed the next point with a drop-shot winner, she stared directly back at Kerber, leaned forward and yelled the two words back louder and longer while shaking a fist.

“She’s had to work on it, really, really, really hard,” Guilbeau said with a laugh in a phone conversation on Tuesday. “The emotion gets everybody, there’s no getting around it. The word I used with her a million times was professionalism . . . I always told her, picture yourself in the final of the U.S. Open. How would you want to emote and handle yourself in those situations? And look, she’s going to be more fiery than anyone you’ll see, but she’s really learned to not have the down moments take her off of her game.”

Collins first burst onto the scene last year, when she started the season ranked No. 160 and won the biggest title of her WTA career in Newport Beach, Calif., in January. She backed the win up with a fourth-round appearance at the BNP Paribas Open in Indian Wells, Calif., and a run to the semifinals of the Miami Open, beating Venus Williams along the way.

In Australia, she has run through No. 14-seed Goerges, No. 19-seed Caroline Garcia and No. 2-seed Kerber, against whom she had 29 winners. Kerber had six.

The win against Kerber made Collins the first women’s player with a background in collegiate tennis to reach the quarterfinals at a Grand Slam since Florida’s Lisa Raymond did it in Australia in 2004. She credits those four years of school as being crucial to her development, and credits her work ethic to her octogenarian father.

“Her father is 82 years old, and he’s the hardest working guy you’ll ever meet,” Guilbeau said. “She came through a really great experience with him. It’s self-taught, but really, he’s the one that taught her based on the old Bjorn Borg videos. She’s a tough kid. Her family didn’t have a lot of the financial backing that a lot of these kids had, so she’s had to develop a tougher skin. … This isn’t an overnight deal. She has worked, and it’s a process — she didn’t skip any steps.”

Collins was one of five American women to reach the fourth round along with Serena Williams, Sloane Stephens, Madison Keys and Amanda Anisimova. Only Williams and Collins made it to the quarterfinals. Now the first through to the semifinals is Collins, whose entourage in Melbourne consists of just her USTA-provided coach, Mat Cloer; her hitting partner; and her strength and conditioning coach.

“Not being a child prodigy, not being a superstar at a young age certainly humbled me, made me in a way work harder for things,” Collins said after her quarterfinal win. “I think I was talented and athletic, but maybe not to the level that other players were at, like, 14, 15, 16. … I was kind of playing from behind because I wasn’t a child prodigy, I went a different route. I wasn’t really sure if I could make it playing professional tennis when I was that age. Going to college was really crucial for me and my development.

“It’s kind of made me hungrier in some ways, not having that, ‘Oh, I’ve always been really amazing at tennis.’ It wasn’t always like that. I wasn’t always great or good.”

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