By ESPNSTAR.com staff
Lee Kyu-hwan fired his side ahead after just seven minutes, before fellow South Korean Nam Geun-young netted in the 24th minute to hand General Trias a two-goal lead at the break.
However, Navy's misery continued in the second half as Song Myung-soo netted a brace and 12 minutes from time, Do Hoan-cheol popped up with his side's fifth to cap off a fantastic day at the office.
The result means General Trias claim the early lead at the top of Group A, above Global on goal difference, after the defending United Football League champions beat Pasargad 3-1 on Tuesday.
Team Socceroo, the final team in the group, are yet to get their campaign underway.
In Group B, Diliman and Forza were forced to settle for a 0-0 draw.
The result means both sides, along with Kaya and Green Archers United are tied on one point apiece in the group, while Dolphins United are yet to play.
Thursday's UFL Cup Results
Philippine Navy 0-5 General Trias International
Diliman 0-0 Forza