Corteza, the 24-year-old former SEA Games 8-ball champion from Davao, thumped Kevin Smith of England, 5-2, and Mauro Ibarra of Mexico, 5-1.
The 24-year-old Orcullo, one of the three Filipino qualifiers here, made an impressive start by beating Aruba’s Ryan Rampersaud, 5-3, then downed Daryl Peach of England, 5-2, to emerge a surprise co-leader in Group 14 with German Ralph Eckert.
Except for Alcano, a first-timer here, the rest of the nine-man RP contingent came through with big wins even as American Earl Strickland fumbled with an early setback in the event he won over Filipino Francisco "Django" Bustamante last year.
Kiamco, who finished fourth in the recent RP vs Europe 9-ball clash in Manila, joined Englishman Steve Davis at the helm of Group 9 with two victories, beating Richard Wolff of Aruba, 5-2, then nipping Russian Konstantin Stepanov, 5-4.
Ramil Gallego split his first two matches in the day, falling to Davis, 1-5, but bouncing back with a 5-2 victory over Lay Ang-boon of Singapore in Group 9.
Also posting a 1-1 record in Day One was Antonio Lining, who lost to German Thorsten Hohmann, 2-5, but downed Scot qualifier Geoff Dun, 5-2.
Bustamante, hoping to finally claim the crown in five tries here, outplayed Canadian-based Filipino Raymond Cruz, 5-3, in Group 2 action for his first win in the elims. Also winning his opening day game was Marlon Manalo, who humbled Charlie Williams of the US, 5-3.
At the end of the group section, the top four players in each group advance to the last 64 and the bottom four are eliminated.
The last 64 will be a race-to-9 duel. The tournament will adopt the winner break format from there. The third round, the quarterfinals and the semifinals will be a race-to-11 affair while the championship will be a grueling race-to-17 clash with the winner running away with the top $65,000 prize.