After conceding a draw in the first game, Humpy was in peak form as she outclassed Trang in all departments of the game to win the two-game mini-match by 1.5-0.5 points.
The Indian ace will now meet Shen Yang Yang of China, who defeated Nadezhda Kosintseva of Russia in blitz games in the tie-breaker following a 1-1 result.
It was Trang's Dutch defence that led to disaster for her in the middlegame. Humpy developed her pieces nicely and gained more space after the opening, and her strategy worked as Trang had no suitable answers.
The Andhra girl was on top after pressing on the queenside and Trang's strategy came crumbling to end the game in 38 moves.
The other Indian in the fray, Dronavalli Harika, was eliminated in the pre-quarters after she went down to Lilit Mkrtchian of Armenia in the return game.
Mkrtchian decided to surprise Harika and prepared a variation that she never played before. The Armenian succeeded in her ploy as Harika made a couple of mistakes in a Sicilian Najdorf defence game. In the middlegame, Mkrtchian increased her advantage and won a couple of pawns before running away with the full point.