The Madang girls were up by five points after their first turn at bat, thanks to some power batting from Eunice Fong and Angelica Takaili.
This forced the Pirates coach to make a change bringing on Vince Tirupia to take over the pitching duties from Lina William.
Pirates hit back in the same inning with William making up in a big way hitting the first home run for the team, bringing the score to 5-1 after the completion of the first inning.
With the home crowd behind them, the Pirates continued to fight their way back with the score at 7-6 in favour of Rovers after the completion of three innings.
But that would be all from the Mt. Hagen girls as the Rovers tightened up their infield, holding the Pirates scoreless for the remainder of the final.
Rovers went on a rampage adding on a further nine runs to win comfortably in the end.
Rovers will now meet the winner of the second preliminary final between Bears and another Mt. Hagen team, the Titans.
The Bears and Titans game will take place tomorrow morning with the grand final to be played later in the afternoon.