MELBOURNE, AUSTRALIA - For 15-year-old Ukrainian sensation Marta Kostyuk, tennis runs in the blood. Whether it holds a place in her heart is a question the youngster is just now learning how to answer. 

On Monday, Kostyuk became the youngest player since Martina Hingis to win a match at the Australian Open, coming through as a qualifier to defeat Peng Shuai in her tour debut. Kostyuk earned a wildcard into qualifying by virtue of winning the junior title last year and became the first 15-year-old to qualify for a Slam since Sesil Karatantcheva in 2005. She is the youngest non-wildcard to win a Slam match since Mirjana Lucic-Baroni at the 1997 US Open.

Kostyuk continued her run on Wednesday, defeating Australian wildcard Olivia Rogowska 6-3, 7-5 to become the youngest woman to advance to the third round of a Slam since that same Lucic-Baroni run at the 1997 US Open. The win extended Kostyuk's winning streak at Melbourne Park to 11 matches and sets up a third-round meeting with her compatriot, No.4 Elina Svitolina. 

"I don't feel special about this because if I feel something different every time I play and beat some record, it's going to be too much," Kostyuk told reporters after her first-round win. "I'm still young and I'm trying not to focus on it."

"I'm just trying to do it in a line, because I'm a person who is up and down all the time, in life, on the court, all the time. These things I'm trying to control. I'm just starting and I have 15 more years in my career."

Kostyuk's mother, Talina Beiko, played on tour and reached a career-high ranking of No.391 in 1994. She's the reason Kostyuk picked up a racquet at four-years-old (more on that below) and she continues to be the most influential voice in her career, one that counts Roger Federer's coach Ivan Ljubicic as her manager. 

"Two weeks ago I played an ITF 25K and I lost in the first round," Kostyuk said. "I lost the first round to a Greek girl. I was up and I had set point and I made some mistakes in that moment. 

"After the match, I was so upset. 'I don't want to go to Australia, I don't know what I'm going to do here, why am I coming here, I'm going to lose first round of qualies.' It was like this. Mom was like calm down, it's fine. That's why we came one tournament before. You learn from your mistakes and it will be better."

"I learned from my mistakes and I actually changed a lot here. So in one week I managed to change so many things, you cannot imagine." 

Kostyuk is playing just her ninth senior event at the Australian Open

Speaking with WTA Insider at the Australian Open, the self-assured and bubbly teenager talked about her love-hate relationship with tennis, how the sport brought her closer to her mother, and why she's trying to focus on the long game.

WTA Insider: How did you start playing tennis?
Kostyuk: My mom was working a lot when I was small and, I don't remember it, but my mom told me that I wanted to play tennis so much so I could see her. I have two more sisters, one older and one younger. I was in the middle but it was the period when my mom was working so much as a coach. I didn't see mom that much. I wanted to see her a lot, so I was practicing. In the summer I was on the court from 8 in the morning to 8 in the evening, from when I was 4 or 5. At the same time I was doing pairs acrobatics, from 5 to 11. We finished fourth place in the national championships.

Tennis was the main goal, so I decided to stop acrobatics. I had to be so careful with my weight and it was so much stress. Evey day I was coming from school worrying about my weight. When I was 11, I decided to stop.

WTA Insider: What did you like about tennis?
Kostyuk: I never liked it (laughing). I never liked it! I remember I got this form from the WTA asking me what was my first memory from tennis and I wrote that I was being mad at mom for feeding the ball wrong. That's what I remember clearly. 'Mom! You're doing it wrong! I cannot put the ball in the court because of you!' I was like 4 or 5. 

WTA Insider: So when did you like it? Or are you still looking for that?
Kostyuk: I was always practicing a lot. I always had to go to school, acrobatics, and tennis, so I was quite a busy kid. But I'm really happy that mom was doing this. 

No one was forcing me. I would be winning, 5-0, 40-0, and I would miss one ball and I would throw my racquet and get so angry. 'How could I miss that!' I was a perfectionist. In school everything had to be good, my marks had to be good. In acrobatics, everything had to be good. It wasn't like I didn't care. I was always stressed. People around me were like Marta, enjoy. 

Now when I'm talking to kids I say, everyone is saying enjoy but I cannot tell you this because I never enjoyed it. Only now, maybe here, I'm starting to understand that nothing is that important. Tennis is not so important that it will change my life. 

Kostyuk poses with the trophy after winning the 2017 Australian Open girls title

I hear a lot of players, maybe not top players, say tennis is my everything, tennis is my life. I don't want to take it like this because if I lose or something happens, it would destroy my life. When I finish my career I want to also be good in other things, not only in tennis. I know a lot of players now they are retiring but they come back because they say they don't have anything to do outside of the tennis. I don't want to be a person like this and that's why I don't take tennis so close to me. 

I never have super goals. I think about what is real. When I reach it, then I make another goal. I don't say that I'm going to be No.1 at the end of the year, because if I don't make it, some part of me will not be the same anymore. So everything's fine. 

WTA Insider: So do you do it now just because you're good at it? What's your motivation?
Kostyuk: I was always good at it but the thing is that I never liked it. When I was small, you could not imagine it (laughing). You had to see me. I would lose one ball and I would start crying, but I would keep playing and I would keep fighting.

WTA Insider: So why keep playing? A lot of kids play when they're young and then it's no fun anymore and they quit.
Kostyuk: My motivation was to be with mom. That was my motivation when I was small. Then I started to win and of course then it was feeling good, and I was winning quite a lot when I was small. Only once, as much as I don't like tennis somewhere deep within me, only once did I want to quit.

It was August 2015. I won Grade 1 Under 14s, and when I came to Ukraine I was like 'Oh, I'm a superstar.' (laughing). Then I was practicing so bad for one week and I lost in the second round ITF Grade 5, then I lost Grade 1 Under 16s in the second round, and I came to Kiev and I said, 'Mom, I don't want to play tennis anymore.' So she said ok, give her time, she'll go to school like the other kids. I didn't play for one week. I didn't touch the racquet. I didn't want to. 

Then I said ok Mom, I want to try again. I had four racquets left because I broke all the other ones before. First practice was ok. Second practice, I break one (laughing). My mom was like, Marta, one more freak out and that's it. I broke another racquet (laughing). My mom was like, Marta, you're done. So I was sitting on the court for an hour and then said "Mom, I'm sorry. I want to play. Please."

Then I started to play and after that, in two months, I did the final of Masters, then I won Orange Bowl, Eddie Herr, and Les Petits As. That's the only time I remember I really wanted to quit. 

WTA Insider: It was only a week. 
Kostyuk: Still, it was a decision. I was working a lot, even when I was small. I was playing a lot. I wasn't so stupid that I would just retire and leave everything I had worked for. I was thinking that I was playing tennis for nine years and just because I lost two matches, I walk away? That makes no sense. I realized, you're not addicted, but you're becoming addicted to the emotions and to the work. You're becoming addicted to this work. 

Kostyuk is managed by former ATP player Ivan Ljubicic

WTA Insider: Nowadays, is it just fun because you're winning? What's the most fun you have on court?
Kostyuk: Now I completely changed my attitude on the court in this tournament. Not before. Just at this tournament. I was a different player in my last tournament. I can change like this but I can also change in the opposite side (laughs). Now I understand what it is to manage myself, not show the emotions and to be all the time pumped. 

You know what's the difference? Now you're on the pros and you start to earn money and it's different because you're playing and it's like you're working. You're working hard, you give energy and you take back with the money. It's worth it.

When you play juniors - I'm so happy that I'm finished with the juniors, I'm so happy - it's experience, but at the same time, you're working hard but you really start to work hard when you're earning money. Because you want to earn more, you want to play better, you don't want to injure yourself. Now I'm starting to realize how it is to not show emotions and have all the time good energy, and I'm starting to really understand that it helps me.

My three matches in qualifying, if I would freak out and behave like I did a week ago, I would have lost all of them. 

WTA Insider: You talked about how you don't want to just be about tennis, that you want to be well-rounded. What do you do to make sure that happens?
Kostyuk: I'm a very open person. I like to communicate with people and I think that is my advantage because then you meet more people and you know more people and maybe after the tennis I will find somewhere in myself. Or maybe family will everything for me. I don't know. 

But I'm just trying to take as much from people as I can. I'm in quite a good circle, with Ivan Ljubicic and Roger Federer sometimes. I'm trying to stay in this circle as long as I can because I want to get as much experience as I can. I'm not trying to be better in math or science, I want to be better in life. 

I know especially with women tennis players, with teams and everything, they are becoming so closed. I like that in my team it's not like this. My whole team, they know that I'm a person like this and they don't want to stop me in this. I like that they are supporting me in this because I know a lot of girls, their teams are pressing them like you can't do this or do that. With my team, I can grow up.

WTA Insider: So does Ivan introduce you to Roger all the time?
Kostyuk: I know Roger. Whenever we see each other we say hi. After matches, because Ivan is watching my matches, he's asking Ivan how my matches are. It's good.

WTA Insider: Ok, now it's time for some quick-fire questions. Most used app on your phone
Kostyuk: Whatsapp.

WTA Insider: Favorite social media platform?

WTA Insider: Favorite food?
Kostyuk: Italian.

WTA Insider: Where do you train?
Kostyuk: In Zagreb.

WTA Insider: Who's your coach?
Kostyuk: Luca Kutanjac

WTA Insider: Who were your tennis idols growing up?
Kostyuk: No one. I wanted to marry Novak Djokovic (laughing). I think he knows it because I was in a Serbian newspaper. "Ukrainian tennis player wants to marry Novak." I have 15 years difference with him and my parents have 18 years difference, so for me 15 was like Oh, it's ok! 

But I stopped wanting to marry him when I was 13. No chance! I was quite a mature person (laughing).