Macatangay, not among the pre-tournament favorites after missing the cut in last weeks Junior World in San Diego, inched ahead of Scott Clayton of California at the head of a big RP assault in various age-levels on Day 1 which saw Miguel Tabuena likewise grabbing the lead in his division.
Tabuena, seeking his first victory in the United States, scored 36 for nine holes at the Landmark Golf Club to lead Meechie of Thailand by two in the boys 8-9 years class with compatriot Bino dela Paz not too far in fourth spot after a 41.
Andrea Legaspi upstaged Dottie Ardina in claiming second spot in the girls 10-under division.
Legaspi, carding a 38 also at Landmark, fell five shots behind local bet Frasier while Ardina could only score a 39. The younger RP bets struggled with Kristina Potenciano scoring 45, Andie Unson 51 and Angela de Villa 58.
Wolen Juan Superal also had an impressive start in the boys 10-11 years, his 71 at the Westin Mission Hills course putting him just one behind Bradley Shigezawa.
John Kier Abdon was running fifth in the 12-13 years class after a 75.
Nineteen RP entries sponsored by Philippine Airlines, Samsung, Global Lighting, Airlift Asia and Philippine Sports Commission are seeing action in the Desert Junior Classic which is the continuation of their US campaign.
Also in the boys 14-15 years, Gino Bunyi turned in a 78 while Aran Olea was a stroke behind at 79.