The Raiders looked the more enterprising side from the start and raced into an 8-0 lead within 16 minutes with tries from Shaun Berrigan and Jarrod Croker, who missed both conversions.
The loss of Dugan and Fensom clearly affected the visitors and the home side closed the gap with an Anasta try following a brilliant offload from BJ Leilua.
The second half was a dire affair, with handling errors from both sides aplenty, but it was Mortimer who put the Roosters in the lead on the hour mark when he latched onto a Kenny-Dowall pass after coming straight off the bench.
Mortimer should have added a second five minutes later when he somehow dropped the ball with the line at his mercy following a bust from Aubusson.
Jake Friend looked to have iced the game five minutes from time, but he dropped the ball over the line after the Roosters had been presented with a golden opportunity when Blake Ferguson knocked on five metres from his own tryline.
The under-strength Raiders tried manfully to score, and Berrigan was denied a try after Ferguson was adjudged to have batted a high ball from Terry Campese into his path.
Anasta then booted his third goal of the game late on after the Raiders were deemed to be offside by the officials.
- AAP