Philadelphia, PA (SportsNetwork.com) - Lydia Ko went on to outlast Amy Yang and win by two shots at last week's ISPS Handa Women's Australian Open, and the 17-year-old from New Zealand tightened her stronghold on the No. 1 ranking in the world.

Ko, who became the youngest ever to claim the world's top ranking three weeks ago, improved 0.72 average points to 10.56. She is now 1.33 average points ahead of No. 2 Inbee Park, who was within 0.55 last week.

Following Ko and Park are former world No. 1 Stacy Lewis and Shanshan Feng at three and four, respectively. Michelle Wie improved one to No. 5 despite not playing last week, dropping Suzann Pettersen one to No. 6.

So Yeon Ryu, Hyo-Joo Kim, Karrie Webb, Lexi Thompson and Q Baek rounded out the top 11 once again from No. 7.

Anna Nordqvist and Na Yeon Choi swapped spots, with Nordqvist up one to 12 and Choi down to 13. Azahara Munoz and Brittany Lincicome remained 14 and 15.

With her second-place finish last week, Yang improved five spots to No. 16. Cristie Kerr fell one to 17, while Mi Rim Lee stayed put at 18. Sun Ju Ahn fell two places to 19 and Jessica Korda dropped one, rounding out the top 20.