City, who won 3-0, took control from the outset with the passing and movement from their front five causing Curtin numerous problems.
The in-form Alex Grayson tested the �keeper early with his low shot, forcing a good save.
Neat play by Ryan Kennedy on the edge of the box set up Shane Boyle who skipped past his marker to score his sixth goal in three games.
After his shot from distance had brought a great save, Grayson scored when he fired across the �keeper into the bottom corner.
Rockingham were dominating and just after the half-hour mark, Boyle was dragged down in the box. The referee awarded the penalty but Kennedy�s shot was saved.
After half time, it was the same story with City�s defensive line under no pressure and the home team�s midfielders dominating possession.
With the crowd demanding more goals, Rockingham stepped up a gear and the impressive Papa Kpatar went close when his strike from distance flew past the upright.
The third goal came when Kennedy�s free kick from 20 metres flew into the top corner.
This week Rockingham are away to Balga, the only side to beat City this year.
The reserves won 5-1, while the under-18s welcomed Kelmscott to Lark Hill wanting to ensure they stayed top of the league.
Callum Ribbans and Mitch Morrin both scored two goals in a 4-1 win.