A large crowd at the venue saw Chachawal take the first frame, but then Boon, a semi-finalist at the 2006 Asian Championship earlier this month, broke the 15-red pack wide open and went on to score a riveting break of 102 points, the first century break of the final stages of the tournament.

After earning a 1-1 tie, Boon played with greater confidence and Chachawal failed to stop the Singaporean from scoring points at will.

Ratchapol, spotted at No 25 in the world professional rankings, was equally impressive in his first outing of the tournament.

The Thai professional showed no mercy to Surasak, making his first ever appearance in the final stages, and fired home breaks of 80, 53 and 89 to breeze through the match in a just a little over an hour.

"The world professional circuit gets underway soon and I need to polish my skills before leaving for the United Kingdom early next month," said Ratchapol.

"The tournament in Suphan Buri provides me with my last opportunity to gain matchplay practice and I am taking it seriously. Last season, I improved my world ranking by seven places and I hope to continue the trend this year."

Five last-16 round matches are scheduled to be played today at the same venue, starting at 9.30am.

Tuesday's last-16 round: Noppadon Noppachorn b Anan Terananon 4-2 (1-55 45-65 69-27 91-33 83-27 72-6)

Yesterday's wildcard round: Keith E Boon (Singapore) b Chachawal Rutphae 4-1 (42-73 102(102)-0 77-7 77-42 70-30); Ratachapol Pu-Ob-Orm beat Surasak Phoochalam 4-0 (85(80)-7 85(53)-8 85-43 93(89)-0).