Clavecilla, who showed up the field with a 74 Wednesday, dropped four strokes in the last seven holes, including a double-bogey 5 on the par-3 No. 16, but he parred the last two for a 39-39 card and a 36-hole aggregate of 152.
That was two shots up on Richie Garcia, who carded a 77, a 36-41 round marred by three straight bogeys from No. 15 with the defending champion expected to make his move today where emphasis will be on stamina.
Three down at the start of the round, Garcia, a former commissioner at the Philippine Sports Commission, actually caught up with Clavecilla with a par on No. 4. But he failed to sustain his charge and bogeyed the next three holes.
Alex Montelibano matched Garcias five-over par card (38-39) as he moved up from sixth to third heading into the final 18 holes of this event organized by the National Golf Association of the Philippines and sponsored by the Philippine Sports Commission, DHL Worldwide Express, WWW Express, Airlift Asia, Inc., Mizuno and Master Sports Corp.
Florene delos Santos, who started the round in second after a 76, fumbled with an 80 and slid to joint fourth with Edwin Arcilla, shooting a 78, at 156.
Yoshihiko Akasaka shot a 78 to post a one-stroke lead over Andres Co in Category II. Hector Moreno carded with 80 for third while a host of others stood just a stroke or two behind, ensuring a spirited battle for top honors in the final round today in the 36-hole tournament for players aged 60-64.
Shigemi Chikama, on the other hand, showed the way in Category III (65-69) with a 75 for a three-shot lead over Alfonso Marcelo (78) and four over Alfonso Mesina (79).
A two-man duel loomed in the Super Senior I group (70-74) with Claro Zablan firing an 84 and Tony Katigbak lurking behind with an 85. Mateo Trinos, Jr. limped with a 93 for third while Ike Aycardo and Ben Narciso carded 95 and 97, respectively.
Juanito Balbin, meanwhile, took a whopping 10-stroke lead in the Super Senior II (75 and above) with an 86 with Enrique Beech in second with 96 and John Camping in third with 100.