She also reached her first WTA Tour quarterfinal that year at the Princess Cup at Tokyo, defeating Ai Sugiyama and losing to Monica Seles.

Asagoe appeared in one WTA Tour final, in Auckland 2003, where she lost to Katarina Srebotnik in three sets.

Her most memorable match was a second-round marathon at Wimbledon 2003, when her stressed-out opponent, Daniela Hantuchová, melted down well on the way to what looked like a routine two-set win.

In doubles, with Akiko Morigami, they won their first-round match 6–1, 6–3, and they were to play against the 14th seeds, Marion Bartoli/Shahar Peer.

Asagoe retired at the 2006 US Open, after losing her third-round doubles match (with Morigami) to the world's top-ranked team Lisa Raymond/Samantha Stosur.