Coetzer turned professional in 1988 and retired in 2004. She won her first top-level singles title in 1993 in Melbourne, and her second later that year in Tokyo.
Coetzer entered the top-20 on the women’s world rankings in 1992 and remained there for most of the next 10 years. She developed a reputation for regularly beating players who were higher ranked than her as she climbed to her career high ranking of World No. 3 in 1997.
As a result of her many upset wins and her small size, she earned the nickname "The Little Assassin."