Thapa, who won a gold medal in the last edition, demonstrated his prowess with a commanding 5-0 victory over Santhosh HK from Karnataka. The Assam pugilist will now face Shashank Pradhan of Delhi in the quarterfinals.
Representing SSCB, Panghal warded off a challenge Punjab's Jayshandeep Singh 4-1 to set up quarterfinal bout against Mohammad Aarif of Jammu and Kashmir.
Meanwhile, 2021 Asian champion Sanjeet knocked out Sawan Gill of Chandigarh 5-0 in the 92kg weight category.
Sanjeet, representing SSCB, will face Naman Tanwar of RSPB in the quarterfinals.
Ashish Kumar from Himachal Pradesh demonstrated his swift and aggressive boxing, secured a first-round knockout victory against Nitish Kumar from Chandigarh in the 80kg category.
The Tokyo Olympian will face Lakshya of SSCB in the last-eight.
A total of over 350 boxers across 13 weight categories are participating in the championships.