MANILA, July 22 -- Filipino Jana Jelena Nicole Diaz boosted her chances of reaching the quarterfinals after posting two victories in the first leg of the Oscar J. Hilado J60 World Tennis Championship at the Rizal Memorial Tennis Center Wednesday.

Diaz downed compatriots Kathlyn Ann Bugna, 6-0, 6-1, and Zacci Elyce Yuipco, 6-3, 6-0, to share the Group A lead with Korean Yerin Lee.

Lee, ranked No. 394 in the world, clobbered Bugna, 6-0, 6-0, and Yuipco, 6-0, 6-0.

Under the World Tennis (formerly International Tennis Federation) rules, J60 events use a round-robin format where the top player from each four-player group advances to the single-elimination quarterfinal stage.

In Group C, Louraine Jallorina defeated American Sofia Bartolata,...