NEW YORK, USA - That Taylor Townsend is still just 23-years-old feels like a typo. The former junior No.1 has been in and out of the tennis spotlight since she won the girls' Australian Open title in 2012 as a 15-year-old and finished the year as the first American girl to finish as junior No.1 since 1992. With a throwback game that recalled Martina Navratilova, John McEnroe, and the crafty serve-and-volleyers that built the sport, she was hailed the future of American tennis.

But with every glow-up, there is a tear-down, and no recent young American prospect has experienced it as harshly as Townsend. Her fitness was questioned publicly, her choices of coaches and training base constantly undermined. The negativity took its toll on the otherwise private teenager, but recently she began to transform those doubts into fuel. 

"I've heard it for a really long time that I was never going to make it, that I wasn't going to be able to break through or do this or do that," Townsend told reporters at the US Open. "Sometimes when you were close and you never quite get over it, it's always the word 'talented' or something like that.

"For me, especially over this last year, I've kind of really embraced that, thriving in these kinds of conditions, being able to prove people wrong. 

"I've always been that way, but I think I suppressed that side of me for a long time. I've just embraced it and it's like, This is the person I am. I love it. I thrive in these kinds of conditions and I think it showed today."

"I've had a lot of people doubting me being able to break through, quote-unquote."

- Taylor Townsend

On Thursday, playing on the biggest court in the world against a reigning major champion, Townsend earned the ultimate validation and vindication of herself and her game. Playing with incredible confidence and aggression, Townsend deployed her throwback game to the fullest, rushing the net over 100 times and gamely saving a match point to stun No.4 Simona Halep in the second round of the US Open. 

"I see a lot of familiar faces in here," Townsend said with a smile, addressing reporters after the win from the main interview room. 

"Just to be able to get over the hump, it's such an amazing feeling because after Wimbledon, I was devastated after I lost to Kiki Bertens after having a match point."

Townsend said she had nightmares about her ill-fated dropshot on that match point, which she missed. Bertens went on to win 3-6, 7-6(2), 6-2 in the second round.

"I put my head down and just worked really hard and just tried to take the positives away from it, just continue to press forward. 

"After we played together, she came in the locker room and she asked me what she has to improve to be better."

- Simona Halep

Flash back six months ago. Townsend's heart was beating out of her chest. She had just taken a 6-1, 6-3 drubbing at the hands of Halep in the second round of the Miami Open, and now she was standing in front her again, this time in the locker room. 

"After we played together, she came in the locker room and she asked me what she has to improve to be better," Halep told reporters at the US Open. 

It wasn't a common move for the American, but something about that moment and that match piqued her curiosity and fueled her hunger for improvement. 

"Something inside of me was nudging me to ask her," Townsend said. "She just kicked my a** in Miami, so I was, like, Screw it, let's see what she felt on the other side of the net. I know what I felt, but I was curious to see what she felt.

"She gave me some good advice. Honestly, she didn't really tell me anything I didn't know, but it was good to hear it from another player, someone I just played, played a couple of times. Especially someone who is at such a high level, has accomplished so much.

"I don't know why I did it, but I did it. It kind of stuck with me. I'm not saying that everything she said I implemented into my training, but it was definitely in the back of my head to remember what she said and also remember why I asked, what drove me to ask that question, kind of that hunger and desire to get better.

"I think I kind of turned that into more of a positive to say, Hey, you can continue to learn and grow."

Taylor Townsend and Yulia Putintseva pose after the 2012 Australian Open girls final. (Getty Images)

"I'm 23. Some of you guys I've known literally since I was 15, 16 years old. It's insane. But it's just growth as a person. I think that's the beauty of this sport, that you can watch people from such a young age kind of develop as people and players.

"For me, I've just evolved. I've always been this person. I think for some years I was lost, lost in a sea of a lot of stuff. But it's nice to be able to come up to the surface and float, eventually swim."

That Townsend's gamestyle proved so effective against, arguably, the best counter-puncher in the game, cemented her belief in her game. A style that was once standard in the game is now unorthodox in an era of slower courts, better racquet technology, and an army of baseliners. In the final set alone, Townsend served-and-volleyed 40 times and approached the net 64 times, putting constant pressure on Halep to come up with high-quality passing shots. 

Halep said she had never played a match with a player attacking the net with such frequency and she struggled to find any rhythm to combat it.

"I think it was really great confirmation that this style of play works, that I can continue to do it," Townsend said.

"In terms of a player, I just feel like this was a huge, monumental moment. It was a very defining moment for me to realize that I belong here."