Nupur recorded a facile 6-2 6-4 in the second round match after staving off a determined fightback from her rival in the second set to enter the last eight.
Nupur next runs into Haryana's Himani Mor, who overcame the stiff challenge of Karnataka's Abilasha Vishwanath 6-1 6-4, for a place in the semis. Abilasha had ousted third seed Aryali Chavan in the first round.
Preeti now meets Maharashtra's Pareen Shivekar in the semis. The latter crushed state rival Supriya Zende, a lucky loser, 6-1 6-0 inside an hour.
Pareen was at her attacking best from the start and maintained that momentum throughout the match.