The 30-year-old Davaoeno followed up his opening 68 by solving the difficult pin placements, clinging on to the lead with a 140 total to hold off former RP Open champion Robert Pactolerin, who also scored a 72 for a 142.
Melvin Eso was the last of three players who played it even, matching his opening day effort for a 144 to be in third, one ahead of fourth-running Country Club Invitational champion Tony Lascuna.
Lascuna shot himself in the foot with a 75 and now has a 145 tally even as Cassius Casas broke par for the first time in a long while with a 71 to be in fifth at 147 like Lito Rempojo (76).
Mars Pucay made a huge jump, shooting a 70 to climb to eighth at 148, a stroke ahead of Roger Cabajar (78) and Juanito Pagunsan (79) in the tourney bankrolled by Korean patron Lee Sung Ho. Engr. Nelson Salazar is putting at stake a share at Buenavista Nature Park for an ace on the 17th.
Bisera has never played in the final flight of amajor tournament and the pressure is enormous, since he will be paired with Pactolerin, the 41-year-old seeking to end a 13-year drought.
Pactolerin, whose last victory came in the 1992 RP Masters, made up for three bogeys in the first five holes with birdies in four of his next six.
He played his front side on No. 10 and a 1-under card was thrown away when his 3-wood off the tee on No. 5 landed in the water.
"Sa last two rounds magkakaalaman. Dahil magkakasama na ang mga leaders,"said Pactolerin.
Only the top 30 scores made it to the next two rounds, and among the big names who failed to make the 155 cut-off line. Among those who failed to make it by virtue of a countback were Rey Alo, Solomon Gines, and Benjie Magada.
Amateur star Juvic Pagunsan soared to a 78 and fell into a tie with his father Juanito and Cabajar for ninth place at 149. He towed nine other amateurs into the final two rounds, leading Mike Bibat, shooting 72-150, by just a stroke.