Thirteen-year-old Pranjala, who had won the under-16 singles title in the CCI Ramesh Desai Memorial All-India Ranking Nationals last May, showed great character as she outsmarted her senior opponent in straight sets, winning it 6-3 7-6(3) to advance to the semi-finals.
Pranjala now runs into second seed Hana Mortagy of Egypt, who prevailed over India's sixth seed Dhrithi Tatachar Venugopal 6-3 7-6(9) in another quarter-final clash.
India's top seed Sri Vaishnavi Peddi Reddy, who is also from Hyderabad, too entered the semi-finals.
Vaishnavi, 17, beat her compatriot and eighth seed Vasanti Shinde in quick time, coasting to a 6-2 6-2 victory.
She will clash with fifth seed Yekaterina Gubanova of Kazakhstan for a place in the final. Yekatrina fought back from the loss of the opening set to overcome fourth seed Teertha Iska of India 4-6 7-5 6-4.
In the boys' singles, unseeded Garvit Batra remained the lone Indian hope by entering the semi-finals along with no.1 seed Goran Markovic of Kazakhstan, no.3 Chih-Chun Tang of Chinese Taipei and no.7 Dmitry Popko of Kazakhstan.
Boy's singles (quarter-finals): 1-Goran Markovic (Srb) beat 6-Alexey Nesterov (Kaz) 2-6 6-4 7-5; Garvit Batra (Ind) beat Kuatbek Abhiyev (Kaz) 6-1 6-2; 3-Chih-Chun Tang (Tpe) beat 7-Timur Khabibulin (Kaz) 6-2 6-1; 7-Dmitry Popko (Kaz) beat Sachin Kumar (Ind) 6-0 5-7 6-1.