Thapa (63.5kg) and Tuguldur went toe-to-toe with their aggressive approach from the start and dealt some heavy blows, making it a very close match.
In the end, it was the experience and quick movement of the leading Indian boxer that helped him triumph over his opponent and secure a 3-2 win by split decision.
Thapa now faces the winner of the fight between Haidara Alasaly and Minsu Choi in the quarterfinals.
Later on Friday, Ananta Chopade (54 kg) and Etash Khan (60 kg) will play against the Japanese Tanaka Shogo and Thailand’s Khunatip Pudnich in their pre-quarterfinal bouts respectively.
Seven Indian female boxers including: Tokyo Olympics bronze medalist Lovlina Borgohainwill kick off their campaign from the quarterfinals on Saturday.
Lovlina, who has changed her weight category from 69 kg to 75 kg, will play her first international tournament in the new category when she takes on the gold medalist of the 2016 World Championships Valentina Khalzova of Kazakhstan.
The other six boxers in action are Minakshi (52 kg), Sakshi (54 kg), Preeti (57 kg), Parveen (63 kg), Ankushita (66 kg) and Pooja (70 kg).