It looked like the team had missed out on a place after a goalless draw against Nadroga on Monday allowed Nadi to accompany Labasa in progressing from pool one instead.
But Navua earned a reprieve after filing a protest against Nadroga for fielding ineligible player Koshmick Kumar. The protest went in their favour and they will now face Lautoka in the semi-final at 9am on Sunday at TFL National Stadium in Suva.
The other semi will be contested between Rewa and Labasa and kicks off at 10.30am at the same venue.
The B division final between Dreketi and Tailevu Naitasiri takes place at 1pm while the grand final starts shortly afterwards at 3pm.
Lautoka hauled themselves back into contention for the title on Monday by beating Nasinu 1-0 and Ba by the same scoreline thanks to a Valerio Nawatu goal.
Rewa made it through in style by defeating Suva 2-1 to claim top spot in pool two. Epeli Saukuru and Solomon Islander George Lui scored in the first spell before Suva pulled one back through New Zealand import Dominic Rowe.