Even after 23 Grand Slam titles and more than two decades of professional tennis, Serena Williams is still fighting to quiet the voice within that wants her to strive for no less than perfection.

The 38-year-old American overcame stiff competition in the second round of the U.S. Open on Thursday, defeating Russia's Margarita Gasparyan in straight sets, telling reporters that she is still working toward giving up her fight for perfection.

"I always feel like I'm not perfect unless I'm perfect. That's not a fun way to live your career and live your life," she said.

The six-time U.S. Open champion is once again gunning for a record-equaling 24th Grand Slam title, coming heartbreakingly close to achieving the goal with four finals appearances in majors since she returned from maternity leave.

Her career is the undeniable product of a relentless and lifelong drive for perpetual self-improvement. But acknowledging perfection is among the biggest challenges she has faced.

"You can't win every single match every time, and that's kind of the pressure I put on myself. It's just completely unrealistic," she said, adding that some of her earliest memories were those of self-torment over her perceived shortcomings.

"I was going to school and doing, like, the alphabet and it wasn't perfect," she said. "I stayed up and kept erasing it until I got it perfect. Then I would cry and then I would erase it and redo it and redo it. I remember I woke up the next day and I didn't finish my homework because I kept erasing it.

"That's been really the story of my life. It's so, so crazy because my daughter does the exact same thing."

Williams claimed her 102nd U.S. Open match win on Tuesday - yet another record broken - and next faces fellow American Sloane Stephens in the third round.

"I feel like every day I'm on a new journey, and in this tournament in particular and this year, it's just a new journey," said Williams. "I feel like I'm on that journey and I'm going in the right direction."