Ami, playing board three, scored a critical 55-move win over Rustom Tolentino to secure a draw for QC A in the second playoff match and preserve a 4.5-3.5 decision over Mandaluyong A.
It was Amis second straight win over Tolentino in the finals.
"I knew I needed to win this because if we ended up tied, Mandaluyong will retain the crown," said Ami who is taking up law at the Baguio Colleges Foundation in Baguio City.
The 26-year-old Ami, playing white, won a pawn in the middlegame of what started as a Queens Gambit match, and nursed the material advantage to victory.
Mandaluyong A had earlier threatened to steal the title away from QC A when Edmundo Gatus exacted revenge on Ilann Perez in 54 moves of an Alekhines defense.
The first two boards ended in draws with Grandmasters Eugene Torre and Joey Antonio settling for a friendly draw after 16 moves of a Trompovsky.
NM Rolando Nolte, who backs up Torre at board two for QC A, halved the point with International Master Idelfonso Datu in 26 moves of a Closed Sicilian.
With his two victories in the finals, Ami matched Torres win-loss record. Both scored 10 points in 13 matches.
QC A bagged P200,000 while Mandaluyong A settled for P100,000.
In the battle for third place, Muntinlupa A edged Manila-DPWH, 2.5-1.5, in the second playoff match to complete a runaway 6-2 triumph.
Oliver Dimakiling scored the lone win at the expense of Rodolfo Panopio at board three. The rest of the matches ended in draws.
Muntinlupa A, bannered by IMs Nelson Mariano and Jayson Gonzales, brought home P75,000 while Manila-DPWH, led by NMs Ben Flores and Rolly Martinez, earned P50,000.