Erica Kathleen "Kathy" Horvath (born August 25, 1965) is an American former professional tennis player. She is best known for upsetting world No. 1 Martina Navratilova in the fourth round of the 1983 French Open, delivering her only defeat for the season.
Horvath was the youngest player to play in the US Open in 1979 at 14 years and five days — this record still stands. She was the youngest player to win the U.S. National 16 and under in 1979.[1] She also is the only player to ever win all four age groups in the U.S. Girls Clay Courts in all consecutive years.
She played on the WTA Tour from 1981 to 1989, winning six singles titles and reaching a career-high ranking of world No. 10 in 1984.[2][1] She reached the quarterfinals at the French Open in 1983 and 1984. She retired with a 176–154 singles record.[3]
Horvath was the only player to defeat Martina Navratilova in the 1983 season (at the French Open), winning in the fourth round in three sets.[1] Navratilova's coaches (Renee Richards and Nancy Lieberman) argued in the stands over strategy, something Navratilova noticed during the match.[4]