In hot conditions and with a vocal crowd of supporters, Flies were always the favourites boosted by the experience and skill of PNG Palais players in Cathy Neap and Helen Abau, and took a 10-4 lead at half time.
The lead was pushed out to 14-4 early in the second half when Abau crossed over in the corner.
But the Royals girls hit back immediately from the restart through a barging Naomi Kaupa who proved too hard to stop close to the line.
An unsuccessful conversion left the score at 14-8 with the Royals needing a converted try in the dying minutes to level up.