Lee Kiefer won bronze at the World Fencing Championships on Tuesday, becoming just the second U.S. woman to earn an individual foil medal at the event and the first since Iris Zimmermann accomplished the feat in 1999.

Kiefer, 17, beat Poland's Martyna Synoradzka 15-12 to reach the semifinal round, but fell 15-10 against three-time defending Olympic champion Valentina Vezzali of Italy.

Lee Kiefer, left, is ranked 13th in the world. Giuseppe Cacace/Getty Images

"It's hard to be happy with yourself when you don't win, but I'm happy with myself," Kiefer told USA Fencing. "Fencing Vezzali and those girls has given me so much more confidence. I started doing seniors three years ago and when I fenced the worlds, that was just my second event as a senior ever.

"I started then and everyone was so strong that it was really depressing coming from Y14 and cadet events. Fencing people who were so much better was kind of a low point and I was really miserable. But the more I improve on people, the more confidence I get now."

The worlds continue Wednesday with men's epee and women's saber, where Mariel Zagunis will vie for her third straight world title.