Manotoc hit just two birdies against four bogeys in a windy day for a 36-34 round at the par-68 layout while Lagman blew a two-under card after four holes with three bogeys in the next five then dropped two more strokes late in the round for a 36-35 card.
Counting their 62 in the opening four-ball format Wednesday, Manotoc and Lagman took charge at 203, one ahead of Paolo Wong and Don Petil, who assembled a 143 for a 204 while erstwhile frontrunner Ryan Monsalve and Lanz Uy groped for form in individual format with a 146 and slipped to third at 205.
The rest stood too far behind to contend for the crown heading to the deciding two-ball, foursome (alternate shot) format of the three-day season-ending tournament organized and conducted by the National Golf Association of the Philippines and sponsored by the MVP Sports Foundation.
Rupert Zaragosa bucked tough pin placements and gunned down five birdies against two bogeys as he fired the tournament-best three-under 65 but teammate Adrian Romero limped with an 81 as they pooled a 146 for a 210, seven strokes off the pace.
Dan Cruz and Luigi Guerrero both shot 74s, their 148 giving them a two-day haul of 214 while Carlo Quimson and Aniceto Mandanas turned in a 73 and 77, respectively, for a 150 and a 216.
Gabby Malaguim and Ivan Monsalve carded a 74 and 75, respectively, for a 149 and 219 while Clare Legaspi sizzled with a two-under 66 but drew an 82 from teammate Felicia Medalla as they scored a 148 for a 214 in the premier group of the event serving as part of the PLDT Group National Amateur Golf Tour.
Meanwhile, Pierre Ticzon (80) and Allan Crisostomo (83) hiked their lead to three in Group II with a 163 for a 233 as Santino Diokno (77) and Miguel Roque (83) combined for a 160 and a 235.
Jimmy Suelo (77) and Allen Embuscado (81) shot a 158 and all but wrapped up the Group III diadem with a 230, seven strokes ahead of Edwin Abesamis and Hermie Salivio, who both made 72s for a 164 and 237. Joey Anciano (82) and Boom Coscolluela (83) assembled a 165 and lay two shots farther back at 239.