Webb used a 3-under-par 68 to pass Feng in Sunday's final round and win the ShopRite LPGA Classic in New Jersey. It was the 39th LPGA Tour win -- and 54th title as a professional -- for Webb, an inductee to the World Golf Hall of Fame.
The result boosts her to 11th in the world rankings.
Choi's tie for 18th in the tournament was enough to lift her past Suzann Pettersen to third in the rankings while Feng, who led after each of the first two rounds of the 54-hole tournament, moves from eighth to No. 7, switching places with Jiyai Shin.
The LPGA turns to the Wegmans LPGA Championship in Pittsford, N.Y. this week, the second of five major tournaments on the schedule. Inbee Park won the Kraft Nabisco Championship -- the first major in 2013 -- in April, a victory that boosted her to No. 1 in the rankings.
The women's world golf rankings Top 10, with rankings points average:
1. Inbee Park, 9.76
2. Stacy Lewis, 8.60
3. Choi Na-yeon 7.80
4. Suzann Pettersen, 7.67
5. Yani Tseng, 6.90
6. Ryu, So-yeon, 6.68
7. Feng Shanshan, 6.32
8. Jiyai Shin, 5.88
9. Ai Miyazato, 5.62
10. Cristie Kerr, 5.57