Twelve months ago, Ukraine's Anhelina Kalinina was ranked No.161 and still chasing her Top 100 debut. The 25-year-old had spent much of her career grinding on the ITF Circuit. She made her WTA main-draw debut in 2015. She wouldn't play another match until 2018. 

But Kalinina has quietly made strides. She came into this week's Credit One Charleston Open ranked inside the Top 50. With wins over Aliaksandra Sasnovich, No.5 seed Elena Rybakina and Alizé Cornet, Kalinina has advanced to the biggest quarterfinal of her career. If things hold up, she could find herself seeded at Roland Garros in May. 

Here are five things to know about Kalinina, who has quickly evolved into a player no one wants to see in the draw:

1. She loves the analytical side of the game

Kalinina was introduced to tennis at the age of 6 by her parents, and she was drawn to it immediately.

"It's a very smart game," Kalinina said. "It's like chess, but you're moving. You have to be smart and you have to be very strong."

"I was looking up to Li Na. She was an inspiration because I liked her style and she was amazing on each surface. Li Na was my favorite."

2. The key to her transition from juniors to the WTA was fitness 

Kalinina was part of the ITF Development Program as a junior and enjoyed a steady progression up to the WTA Tour. She said the biggest adjustment was physical.

"The biggest challenge was that I was still quite small," Kalinina said. "My first professional tournament was an ITF 10K and I was 15 years old. It was already powerful girls and I thought I had to improve the physical part. I was quite weak. 

"I didn't feel that way in the juniors. I had to improve my legs, my body, and my strength to be ready to play against women, not girls. That was the most important part."

But once she got her fitness improvements sorted out, Kalinina attributes her success to all the experience she's gained competing on both the ITF and WTA Tours.

"I started to understand the game a bit better, what I have to do from my side, what are my strengths," Kalinina said. "I understood that I can beat these players, that I can play with them. I think that's it."

3. She went on a tear on clay last summer to make her Top 100 debut 

Kalinina's ranking surge began last summer on the clay, where she ran off back-to-back ITF Tournaments to win a $60K in Montpellier and a $100K in Contrexeville. Her run launched Kalinina into the Top 100 for the first time and she did not stop there. She built on that success to immediately make her first WTA final in Budapest, where her 14-match winning streak was snapped by Yulia Putintseva.

"I think that was the first time I realized I could do a lot, that physically I was much better. Before, I wasn't sure that I could win nearly three tournaments in a row. So that was a little bit of change. 

"So it wasn't one win over someone that made me believe. It was that I felt physically better and mentally, I felt that I could do this in three tournaments in a row. That was the moment I thought you have to grow and you have to move your a--."

4. She travels with her husband

Kalinina is coached by her husband, Anton Korchevskyi, a former junior player whose career was cut short due to a back injury. 

"He's doing 200% job all the time," Kalinina said. "My fitness coach is in Ukraine because of the tough times. He cannot travel. So I'm just with my husband 24/7 and he's doing everything. 

"Our goals were to be healthy and go further. I started the year with a completely different calendar. Usually I was playing ITFs in January, but this time I played Melbourne, Adelaide, Australian Open, big events. My goal is to play the full calendar with the top tournaments and test myself there."

Kalinina is thrilled to get a chance to play all the top-tier WTA tournaments she had only heard about. "I never played Charleston and I was really looking forward to this tournament," Kalinina said. "I've never played Madrid and Rome. I never played Miami until last week. It was amazing. I am so excited to compete at these big WTA 1000 events. And I'm really looking to the grass season. 

5. She's champing at the bit to test herself against the best

Now that Kalinina has broken the Top 100, her main focus is on testing herself against the game's best to see just how far she can go. 

"I think I was happier to break the Top 100 than the Top 50," Kalinina said. "Now it's like, 'I have to prove three times more - better serve, better movement, better everything.' I have a lot of goals now. It's not about happiness. I would be happy whether I am No.22 or No.82. 

"I just want to be healthy and improve. Improvement is the most important. It's just such a high-quality field at this level. You have to improve yourself and not think about the rankings. 

"I'm happy that I don't have to play ITFs, I can go to play Madrid, Rome, to test myself there. I was happy when I broke the Top 100 because it meant that I could play in the main draw at the US Open. All the time I was playing qualifying. Mentally I thought it was a great step. For me, it was the priority to play main draw at the Slams."

Charleston: Kalinina edges past Cornet to reach first WTA 500 QF