Joining Mhasde in the Final Four are compatriots Daksh Kukreti and Ribhav Saroha.
Kukreti advanced after top seed Dharma Pantaratorn of Thailand retired in the third set. The score was 6-3, 5-7, 4-1.
Sahona, seeded No. 7, prevailed over Max Johansson of Chinese Taipei, 6-2, 6-2.
Meanwhile, top seed Yerin Lee of Korea downed fifth seed Stefi Marithe Aludo, 6-3, 6-0, in the girls division of the event offering World Tennis (formerly International Tennis Federation) points.
Lee, ranked No. 393 in the World Juniors, will face No. 8 Sorvisa Kulphisanrat of Thailand, who shocked No. 3 Gwen Emily Kurniawan of Indonesia, 6-0, 6-2.
Now on its 18th edition, the annual tournament has been renamed in honor of the late PHINMA Corp. chairman emeritus Oscar J. Hilado in recognition of his lifelong support for and contributions to Philippine tennis.
Past champions include Alexandra Eala, Francis Casey Alcantara, John Bryan Otico, Arthur Craig Pantino, Khim Iglupas, Tennielle Madis and Aludo.