Veteran penalty corner specialist, Sohail Abbas, celebrated his captaincy debut with a rasping drag-flick goal.
Three-time champions, Pakistan, who lost last year's final to Australia through a golden goal, squandered a two-goal lead to allow the tough-tackling Argentina draw 2-2 level, but then scored twice in the last five minutes to assert their supremacy.
Pakistan opened the scoring in the 34th minute, when they just had nine players on the field.
After a fine solo run, Shafaqat Rasool sent a diagonal ball that was picked up on top of the circle by Muhammad Irfan, who beat Argentine goalkeeper, Juan Manuel Vivaldi, with a firm hit.
Skipper Abbas made it 2-0 in the 50th minute with a firm shot that beat Vivaldi and went high into the net.
Down 0-2, the Argentines came back strongly and exploited the gaps in Pakistan's own defence.
Gonzalo Peillat reduced the deficit with a penalty corner conversion in the 53rd minute when their star striker, Pedro Ibarra, was off the field due to a yellow-card suspension.
Argentina were back on level terms at 2-2 in the 62nd minute as Mathias Parades moved behind Pakistani defenders to capitalise on a through ball from Mathias Villa, slotting it into the boards.
However, Pakistan, missing several seasoned players who are facing disciplinary action for playing in the World Hockey Series in India, scored two field goals to clinch full points from the first outing in Ipoh.
Haseem Khan put Pakistan in the lead again by deflecting in a shot from Irfan in the 65th minute and Muhammad Waqas rounded off the scoring with a brilliant goal in the penultimate minute from a rasping cross by Shabbir Ahmed.
While Argentina will face New Zealand in their next match on Friday, Pakistan will play the Black Sticks on Sunday.