There was another one-game roll-off between two Hong Kong finalists after the pair tied in sixth position with 2116. Joshua Chow beat team-mate James Lui 201-168 to make the cut for the stepladder shootout.
Rachmadian, who picked up 70 million rupiah as first runner-up, won the first match against fifth-seed, Hassan Alshaikh of Saudi Arabia and sixth-seed Chow, 199-172-183 to advance to the next match.
The Indonesian defeated third-seed and newly-crowned Classified division Masters champion, Sukinto Wijaya of Indonesia and Youth division Masters champion, Muhammad Azizi Naim of Malaysia, 254-175-230 to challenge the second seed.
There was no stopping Rachmadian as he dispatched top qualifier and second-seed, Chong Jun Foo 247-188 to face the Thai in the title match. Chong, who settled for second runner-up, took home 35 million rupiah.