Goals from Fuseina Mumuni and Millot Opoku plus a sensational hat-trick by captain Mukarama Abdulai handed the Black Maidens all three points at the Estadio Charrua in Montevideo.
The win has put Ghana top of Group A but only due to a better goal difference against joint-top leaders New Zealand, who beat Finland 1-0 in the other group game.
Evans Adotey's outfit will hope to make it two wins on the bounce when they face Finland in their next game on Friday.
It was Mumuni who started the rout in Tuesday's game, hitting the ball on a lovely turn into the net after being picked out by Abdulai, who took a great run down the left.
Five minutes after the 20th minute opener, Abdulai turned finisher, beating her marker to head home Grace Animah's sweet cross from the left.
Pokuaa, who had come on for injured Mumuni in the first half, added her name to the score sheet with a sweet solo run and finish on 66 minutes. Once again, the goal came from the left.
Then there was finally a goal from a work down the right when Pokuaa flicked a cross to Abdulai, who made no mistake with her shot from close range 12 minutes to full-time.
In the first minute of stoppage, Abdulai completed the annihilation, this time, picking a loose ball in the box and coolly planting it into the net.
Ghana are hoping to better their third place finish at Azerbaijan 2012, a tournament where they similarly thrashed Uruguay 5-0 in the group stage.