Yang defeated Seo Hee-kyung on the first playoff hole Sunday at the LPGA KEB-HanaBank Championship in South Korea to claim her first LPGA title.
Yang moves from 27th to No. 18 in the rankings. Seo improves 17 places to 27th.
Pettersen tied for third in the tournament and cut into Park's hold -- now less than 0.9 average rankings points -- on the No. 1 ranking. Park has been atop the rankings for the last 27 weeks.
Pettersen, if she catches Park, would be the ninth woman to be No. 1 since the rankings were instituted in February 2006.
The LPGA continues its Asian swing this at with the Sunrise LPGA Taiwan Championship. Pettersen won the event last year, finishing three strokes better than Park, who was the runner-up.
Lydia Ko passed Ryu So-yeon for the No. 4 spot in the rankings in the only change in the Top 10. Ko didn't play in South Korea where Ryu ended up tied for 22nd. Ryu tied for seventh in the event in 2012.
The women's world golf rankings Top 10 listing player's name, home country and ranking points average:
1. Inbee Park, South Korea, 11.98
2. Suzann Pettersen, South Korea, 11.09
3. Stacy Lewis, United States, 9.96
4. Lydia Ko, New Zealand, 7.12
5. Ryu So-yeon, South Korea, 7.05
6. Choi Na-yeon, South Korea, 6.93
7. Feng Shanshan, China, 6.38
8. Karrie Webb, Australia, 5.99
9. Catriona Matthew. Scotland, 5.40
10. I.K. Kim, South Korea, 5.37