Samantha Stosur ousted in semis
The 134th-ranked Chang broke Stosur twice in the opening set. She eliminated three seeded players on the way to her first career WTA Tour final.
Need the scores from any match played in today's tournaments? Results
Watson broke Doi four times in the second set to make up for losing her own serve three times.
The 20-year-old Watson also will be appearing in her first career WTA final -- just three weeks after Laura Robson became the first British woman in 22 years to reach a title match.
Copyright 2012 by The Associated Press
MORE TENNIS HEADLINES
- Djokovic tops Gonzalez at BNP Paribas Open
- Jankovic defeats Wozniacki at Indian Wells
- Retired player Baltacha, 30, fighting liver cancer
- Murray says back feeling better after surgery