Karli Webster, a 20-year-old from Santa Clarita, CA, won her The Voice Battle this season against 16-year-old Addison Agen from Indiana.

Facing off for only one spot on Miley Cyrus' team, both girls -- who were paired because of their similar voices -- sang a slow rendition of "Girls Just Want to Have Fun" by Cyndi Lauper, and their Battle aired on Monday night's Season 13 episode on NBC.

Miley admitted during rehearsals that she was going to lose sleep over having to choose between these two talented artists.

"Neither me or Addison -- we were very honest with each other from the beginning, because we're very close friends... and we gave each other really good, honest feedback when it came to the song. And we would try to ask each other, like, 'What do you think is going to happen?' But truthfully, neither one of us had any idea what Miley was going to do," Karli told Reality TV World in an exclusive interview.

"And we were both just very clear about the fact that it wasn't about who is more talented, because we felt as though it was literally a level playing field when it came to our talent. It was all going to be up to what kind of style Miley wanted on her team. So we really had no idea what she was going to do."

After the Battle, Miley confessed that pairing the girls together crushed her heart into "1,000 pieces" but their amazing performance was worth her pain. Miley said it was the hardest decision she's ever made as a coach on the show.

With that being said, Miley went with her heart and opted to advance Karli to the next round because her voice floated over Addison's grounded and solid sound. Miley also considers herself a genuine fan of Karli's style and artistry, so it only made sense that the coach kept her on her team.

"We were both kind of shocked! We were both shocked when she called my name, but we had planned and worked so hard for the outcome that one of us would get stolen. We were pretty confident that [Adam Levine] was going to steal whomever didn't win the Battle, so thankfully that happened!" Karli gushed.

In fact, both Adam and Jennifer Hudson wanted to steal Addison. Jennifer insisted she wanted to keep "the girl power going" and that Addison is a star, but Adam pointed out that Jennifer never turned around for her in "The Blind Auditions," proving he's been more passionate about her from the start.

Addison ultimately picked Adam as her new coach, and Adam said if he can unlock that something special he sees in her, it's going to be crazy.

"We were both shocked, I think, by the result just because it could have easily gone the other way," Karli recalled to Reality TV World. "So it was very shocking, but we were both very happy that it worked out the way that we wanted."

Once the Battles come to an end, The Voice's "The Knockout Round" will commence and feature first-season American Idol winner and upcoming Season 14 The Voice coach, Kelly Clarkson, as the remaining artists' key adviser.