The 24-year-old flyweight from Cagayan de Oro toppled Zov Gang of China on points, 33-21, to set up a crucial bout with defending champion Jerome Thomas from France on Thursday.
Paylas victory somewhat erased the effects of the loss absorbed by Arlan Lerio in the bantamweight division where the comebacking Olympian from Mindanao absorbed a close 25-22 decision from Han Sung Moon of South Korea to join teammates Joegen Ladon and Florencio Ferrer at the sidelines.
Earlier Monday night, Ladon absorbed a 27-18 decision from Frenchman Dangnoko Boubakar in the featherweight class while Ferrer was routed by Romanian Lon Dan, 26-8, in the welterweight division where he scored an impressive RSC-O win over his rival from Brunei in the second round in Sundays openers.
With the unexpected early exit of Lerio, the fate of the Philippine contingent, sent here by Revicon with support from the Philippine Sports Commission, Family Rubbing Alcohol, Accel and Pacific Heights, now rests on the shoulders of Payla and light flyweight Harry Tañamor.
"It will be a very tough uphill battle for the two boys (Payla and Tañamor). But I am confident that the RP Revicon Team will not go home without a medal," Lopez vowed.
Tañamor, bronze medalist in the last edition of this championships in Ireland in 2001, drew a first round bye and was to fight Indonesian Bonix Saweho in the round-of-16 late Wednesday night.
Meanwhile, favored Cuban bantamweight Guillermo Rigondeaux Ortiz was upset Tuesday by Agasi Mehmet Agaguloglu of Azerbaijan.
Agaguloglu had lost to Rigondeaux, the world champion and Sydney Olympic Games gold medalist in two previous outings, but triumphed, 16-13, Tuesday.
Cuban pride was salvaged in the welterweight division when Lorenzo Aragon Armenteros defeated Bulent Ulusoy of Turkey, 18-17, and heavyweight Odlanier Solis Fonte beat Spiridon Kladouhas of Greece.