Twelve of the 16 LPGA members in the 32-player field won their opening matches versus their JLPGA counterparts Thursday at Sohsei Country Club.
Sorenstam, the top-seeded player on the LPGA side, won the seventh, 10th and 15th holes before halving the 16th to take the day's first match. Nasu, seeded 16th for the JLPGA, failed to win a single hole during her match with the Swede.
Sorenstam, ranked first in the world with six wins in 2001, will face the LPGA's No. 9 seed Michele Redman in Friday's second round. Redman beat Kasumi Fujii 2 & 1.
This event, which was played as a stroke-play team competition since its inception in 1979, switched to an individual match-play format this year and offers a first-place prize of $144,000.
The first round featured 16 head-to-head matchups between the LPGA players and the JLPGA players. Players from each tour were seeded one through 16 based on their position on their tour's money list.
Six seed Kaori Higo was the first JLPGA golfer to earn a victory when she bested Nancy Scranton 1-up in the sixth scheduled match.
Laura Davies, who won the WPGA International Match Play event in Scotland last month, came from behind to beat Chieko Amanuma. The big-hitting Brit stumbled with bogeys on the first two holes but rallied to win three of the next six en route to a 2-up victory. Davies came into the contest the 15th LPGA seed while Amanuma was the No. 2 seed from the Japanese circuit.
Lorie Kane and Emilee Klein were each on the winning end of lopsided matches Thursday. Canada's Kane won six of 15 holes to dispatch Midori Yoneyama 5 & 3, and Klein brushed aside Fuki Kido 5 & 4, closing out their match by taking the ninth, 11th, 12th and 14th holes.
Se Ri Pak, the only LPGA player with a chance to catch Sorenstam for the 2001 money title, took an early 3-up lead then watched Michiko Hattori win three straight holes around the turn to square the match. Pak grabbed the 12th and 15th holes to prevail 2 & 1.
The 16th-seeded Jill McGill upset the JLPGA's top-earner, Yuri Fudoh, with a 1-up triumph in 19 holes. Fudoh came into this week 14th in the world, the highest Japanese player in the rankings.
Three other showdowns needed extra holes in round one. Kaori Harada outlasted 2000 Solheim Cup hero Carin Koch of Sweden in 20 holes. Rachel Teske, 3-down after 13, won three of the last five scheduled holes to force a 19th and got by Ikuyo Shiotani, and Aki Takamura edged Sophie Gustafson in 20 holes.