Things are only likely to get tougher for Ratchapol from this point onwards, as he is scheduled to take on the winner of last night's clash between talented Chinese Liu Song and Phaithoon Phonbun, winner of the fourth ranking event late last month, in the quarter-finals on Thursday.
A little after Ratchapol's victory, pre-tournament favourite and world No. 23 Michael Holt of England recorded a convincing 4-1 over reigning Asian champion Supoj Saenla in a contrasting manner.
Holt started off in a fine manner as he needed only two visits to the table to take first frame and then a break of 58 points proved enough to give him a 2-0 advantage.
Supoj orchestrated a recovery in the third with a break of 88 points, but that only turned out to be his last hurrah. Michael had a break of 75 in the next and then another 62 in the fifth to wrap up the match.
Earlier in the day, Noppadol Sangnil was also in an impressive nick to beat Wanchana Poomjang 4-2 and roll into the quarter-finals, where he faces Holt.
Meanwhile, the local interest has been pinned on the last 16 round clash between Chanthaburi-native Issara Kachaiwong and Englishman Stuart Pettman, No. 53 in the world, on Wednesday evening.
Issara, ranked No. 1 in Thailand and winner of the Asian title last year, has already won the hearts of his large army of fans here when he scored clearances of 135 and 127 to whitewash Suriya Suwannasingh in the last 32 round on Sunday.
Pettman, on his part, is a tough nut to crack. He played impressively in the first ranking tournament in Hua Hin a couple of months ago to beat both Issara and Ratchapol on his way to capturing the top honours.
In other matches on Wednesday, veteran Praprut Chaithanasakul plays young Nitiwat Kanjanasri, Kobkit Palajin faces Jessada Posukarn and Navin Hengsomboon meets Suttipong Chansri.
Monday night's wildcard round: Michael Holt (England) beat Saharat Charoensak 4-0 (81-35, 92(83)-6, 100(100)-6, 83-45)
Tuesday's last 16 round: Noppadol Sangnil beat Wanchana Poomjang 4-2 (61-58, 88-24, 86-0, 1-78, 3-73, 72-32); Ratchapol Pu-Ob-Orm beat Chatchawal Rutphae 4-2 (73-47, 51-31, 60-58, 35-89, 16-70, 61-25); Michael Holt (England) beat Supoj Saenla 4-1 (89-31, 62-28, 7-105(88), 75(75)-1, 76(62)-6)