Five-time Asian medallist Thapa, competing in his third world championship, produced a fine tactical performance to prevail 5-0 against Kenya's Victor Nyadera.
Tokyo Olympics-bound Panghal out-punched familiar foe Saken Bibossinov of Kazakhstan 5-0. Meanwhile, Thapa dominated top-seeded defending champion Bakhodur Usmonov of Tajikistan to make the final.
World Boxing Championships 2019: Indian boxers are closing in on Kazakhs and Uzbeks, says high-performance director Santiago Nieva
Indian boxers' unparalleled performance at the just-concluded men's world championship shows they are "closing in" on traditional powerhouses such as Kazakhstan and Uzbekistan, High-Performance Director Santiago Nieva has asserted.
World Boxing Championships 2019: 'Happy' Amit Panghal says he wants to complete unfinished business, get the best prize
Panghal defeated Kazakhstan's Saken Bibossinov 3-2 in the semifinals here on Friday to become the first Indian male boxer to make the world championship summit clash.
World Boxing Championships 2019: Amit Panghal, Manish Kaushik secure record two medals with quarter-final wins
In the last-four stage of World Championships, the Haryana-pugilist Amit Panghal will be up against Kazakhstan's Saken Bibossinov.