PLDT Home TVolution booked a spot in the semifinals, stunning Petron, 16-25, 25-21, 25-18, 25-22, on Sunday in the Philippine Super Liga All Filipino Conference at Cuneta Astrodome.
Lou Ann Latigay scored 18 points, all from spikes, while Sue Roces had 14 for PLDT, the underdog in the match after finishing the elimination round with a 2-4 card, in sixth spot.
The Dindin Santiago-powered Petron entered the quarterfinals after winning four of its six elimination-round matches and looked set to march on to the last four with a quick first set win.
But Power Attackers fought hard to turn back the Blaze Spikers and set up a match against early semifinalist RC Cola-Air Force.
The Power Attackers meet the Raiders on Sunday at 3 p.m. also at the Astrodome.
PLDT coach Roger Gorayeb now hopes to move on to the finals after a tough stint last conference where they topped the eliminations only to fall to Cignal in the knockout semifinals.
"Sabi ko sa kanila ayaw ko na maulit 'yung dati, hindi na ako papayag na maulit 'yun" said Gorayeb.
"Isa pa naka-recover kami sa pangit na first set namin, psychological nga lamang na sa amin 'yung kalaban kasi naka-isang set na sila, kaya ni-remind ko lang 'yung mga players na wala nang bukas 'to, treat this game as a championship game," he added.
Although Petron dominated the net with 15 blocks to just three of PLDT, the Blaze Spikers gave away 34 through errors.
"Si Dindin ang tina-target namin, kasi receive na niya palo pa niya, kaya doon kami puntos ng puntos," said Gorayeb.
Santiago had 23 spikes, four blocks and one service ace for Petron.
Mina Aganon and Jozza Cabalsa also had 12 and 10 markers, respectively, for the Blaze Spikers.