Lakshya Sen couldn't overcome the relentless Hu, losing 19-21, 19-21 in a thrilling contest.
A gold medallist at the 37th National Games, Mannepalli was trailing 4-7 in the first game before rallying to 12-9. He then took control and scored six straight points from 15-11 to seal the game.
Later in the day, Commonwealth Games champion Lakshya Sen will face Chico Aura Dwi Wardoyo of Indonesia.
Lakshya Sen defeated Lanier 21-17 21-11, securing a handsome prize purse of around Rs. 36 lakh.
Indian shuttlers Lakshya Sen, Ayush Shetty, and Tharun Mannepalli progressed to the second round of the men's singles competition at the Macau Open Super 300 badminton tournament after registering fine wins on Wednesday.
India's Lakshya Sen came up with a spirited performance to overcome Hong Kong China's Angus Ng Ka Long in three games
Rankireddy and Shetty won 21-12, 21-16 in a quarterfinal match that lasted 49 minutes.