Egged on by a boisterous hometown crowd at the Rizal Memorial Stadium, the Filipinos took control early as they closed out the four-nation meet undefeated counting victories over Singapore and Chinese-Taipei.
Oli Saunders got the Philippine offensive machine humming with three penalty kicks for an early 9-0 lead which the Filipinos protected the rest of the way.
Skipper Michael Letts scored the first PH try, and another solid kick gave the Filipinos a 16-0 advantage 30 minutes into the contest.
Sri Lanka, a side that has been campaigning in Division I up until last year, scored its first try eight minutes into the second half for 8-23, before connecting again seven minutes later to make a game out of it, 15-23.
The Sri Lankans actually came within five, 18-23, after converting on a penalty kick in the 26th minute before Justin Coveney rescued the Volcanoes from a possible implosion in the 31st for what turned out to be the final score.
And after thwarting numerous Sri Lankan offensives and preserving the win, the squad huddled up in midfield in prayer before exchanging high-fives with fans in the stands.
The Asian Top 5, which the Volcanoes are now eligible to join, will seed at least one Asian nation to the Rugby World Cup to be held in London in 2015.
The Volcanoes are also expected to rise in the International Rugby Board (IRB) rankings. They came into the tournament as the 62nd-ranked team in the world.
Singapore, 56th in the world, was the first victim of the Volcanoes, 37-20, before the Philippines scored a 34-12 whipping of the Taiwanese last Wednesday.
With Chinese-Taipei ranked 58th, the Philippines was the lowest-ranked side coming into the tournament. Sri Lanka ranked 43rd.
The Philippines is also one of the youngest members of the IRB, having gained recognition only in 2008 and playing mostly Division III matches until two years ago.