Liem defeated GM Vishnu Prasanna of India, taking his third win at the event.
Liem has 3.5 points and stands ninth. He will face Nodirbek Abdusattorov of Uzbekistan in the next round.
Another Vietnamese Nguyen Anh Khoi also won, beating Seyed Kian Poormosavi of Iran. He has three points and ranks No 35. His next rival will be GM Aravindh Chithambaram of India.
The event ends on April 9.
