Tseng defended her title at the Honda LPGA Thailand 2012 with a closing-round of 6-under-par 66 Sunday. She was 20-under over the last three days and 19-under 269 for the tournament.
That allowed her to pass Miyazato, who finished one stroke behind at 18-under.
The win only kept Tseng's hold on the top spot tight. She has a ranking points average of 16.63 -- nearly twice the figure for the No. 2-ranked player.
Miyazato, who was once ranked No. 1, moves from 11th to No. 9 because of her showing. That was part of a juggling at the lower section of the Top 10 as Stacy Lewis improves one spot to No. 8, still ahead of Miyazato, with Brittany Lincicome slipping from eighth to 10th and Kim In-kyung forced from No. 10 to 11th.
Paula Creamer is No. 5 with an average of 7.29 while Ahn Sun-ju (7.01) is sixth and No. 7 Jayai Shin is at 6.84. Lewis's average is 6.24, only ahead of Miyazato's 6.24 because of more tournaments played. Lincicome's average is 6.19.