Morton kick-started their season thanks to some generous defending from Arbroath allowing them to score three second half goals.
Despite Morton enjoying good possession thanks to the influential Paul Walker pulling the strings in midfield, and Arbroath forcing a number of early corners, it took until the half hour mark for either keeper to be called into action.
Euan Donaldson's curling free-kick was heading for the top corner, but David McGurn did well to scramble across his line and push the ball over the bar.
Unsurprisingly, Morton's first effort which tested Neil Inglis came from Paul Walker after some sublime skill on the edge of the box to fashion a shooting opportunity. However, his powerful effort was well held by Inglis.
Within a minute of the restart, Paul Walker again tormented the home defence and fired a shot at goal, but unfortunately for the midfielder this time his effort struck the post.
However, only two minutes later Morton took the lead. Alex Williams surged into the box and fed Peter Weatherson whose low shot just eluded Inglis and trundled into the net.
The away side's tails were up and on 60 minutes they doubled their lead.
After another strong run into the box, man-of-the-match Paul Walker, found the room to blast a shot at goal from the tightest of angles and although Inglis did well to parry his effort, the ball rebounded off defender Steven Rennie and into the net.
Arbroath's misery was complete on 75 minutes when Morton scored a third thanks to a howler from keeper Neil Inglis.
Jason Walker hit a speculative effort at goal and when Inglis went to pick it up, it rolled through his hands and into the goal.