Declan McManus' double sent Morton to the top of Scottish League One and dumped Stranraer down to third.McManus scored twice in four first-half minutes to leave Morton at the summit with one game left to play.It was Stranraer, whose own title hopes suffered a damaging blow, that started the brighter and Morton goalkeeper Derek Gaston produced a sublime save to keep out Frank McKeown's header before Sean Winter sent another effort just off target,But the visitors made the breakthrough five minutes before the break when McManus stroked home from the spot after Peter MacDonald had been fouled.And it was two just four minutes later when McManus headed in Ross Forbes' cross.Gaston was kept busy in the second half, saving a long-distance shot from Jamie Longworth before Morton's task was made more difficult in the 77th minute when Ricki Lamie was dismissed for a shocking tackle on Daniel Stoney which saw a brawl erupt between the two dugouts.Stranraer could not capitalise and they ended the game with 10 men when Christopher Aitken was dismissed for an elbow.