Powered by five national team mainstays, Zamboanga shook off a sluggish start and fought back from a 0-3 deficit in the first inning then pulled away in the sixth en route to an 11-4 victory over Cebuana Lhuillier.
The Zamboangueños worked behind two RBIs by Southeast Asian Games veteran Edgardo Alvarez to draw level at 3-3 before Lan Perez scored in the fourth to shove the team on top.
But it was in the sixth inning where Zamboanga showed its fierce form as Rodel Marcos scored two RBIs while Joey Cruz and Alvarez combined for the next two and a forced run from the team to seal the victory.
"We were just looking for a good game, but it turned out to be an impressive one. The key here was our comeback in the second inning where Alvarez had two RBIs," said team manager Luis Climaco, also a councilor in Zamboanga.
Over at the Barangay Sto. Niño in Marikina, the softbelles of UP and UST blanked their respective opponents for a rousing start in this event organized by the Amateur Softball Association of the Philippines which drew 25 teams, including 17 in the mens side.
Dionie Macasu pitched a perfect three-inning game to propel UP IX to a 16-0 rout of Makati.
UST scored a similar shutout victory over Mail and More, 4-0, while Northern Mindanao and Caloocan completed the opening day winners in the womens division. Northern Mindanao edged Rizal, 3-2, while Caloocan thumped La Salle, 6-2.
Antipolo, however, produced the biggest rout when it blasted Tacurong, 15-0, at the Taguig grounds.