Watch: Aleksandra Krunic wows the crowd with her defense

NEW YORK -- All 21-year-old Aleksandra Krunic wanted to do at the U.S. Open was qualify for the main draw. Yet there she was on Monday night, playing on Arthur Ashe Stadium under the lights against two-time Slam champion and two-time U.S. Open finalist Victoria Azarenka (having already beaten Wimbledon champion Petra Kvitova one round earlier) for a spot in the quarterfinals. And the diminutive Russian-born Serb had all of New York behind her. She would lose 4-6, 6-4, 6-4, but it was a performance to remember. 

"I was once again surprised with the support of the crowd," Krunic said after the match. "Sometimes I felt for some moments that they were cheering louder for me than for Vika, and I really appreciate it. Yeah, I think I should be proud of myself."

Krunic endeared herself to the 22,000 fans on Ashe Stadium with her grit and guile, showing off some brilliant footspeed and shotmaking to leave Azarenka flummoxed for much of the match. No single point got the fans on their feet more than this one though, which saw Krunic play some brilliant defense before scrambling forward to finish the point. Her celebration was awesome:

All in all, Krunic won six matches in New York (three in qualifying and three in the main draw), beating No. 27 Madison Keys, No. 4 Kvitova, and pushing Azarenka to the brink. The constant refrain from writers and commentators during Krunic's matches was, "Where has this woman been?" She's been playing in the ITF circuit without much success, which is perplexing given her big serve, ability to hit for power, and speedy defense. Krunic said she is leaving New York with a better understanding of what she's capable of on the court. 

"Some people tell me, 'You're so mature for your age,'" she said. "Now I think I started really using what I know also for myself and started maybe loving myself a little bit more. I'm more mature in some situations on the court and I support myself much more, because I get the support from the crowd. But if I'm all the time giving negativity to myself, it's not going to help. I think that's the main thing that I improved and I learned about myself, that, yeah, I am much more positive and I'm much more tolerant to myself."

Here's hoping we see more of Krunic in the future. She's a fun one to watch.