Arbroath missed the chance to go second in the Championship as Morton found a late equaliser at Gayfield.
Findlay Marshall shot the hosts in front early in the second half following good work from David Gold.
Jackson Longridge then struck from close range on 80 minutes, forcing in a cross from Owen Moffat, to earn the Greenock side a share of the spoils.
Arbroath remain third, level on points with Raith Rovers and five behind early pacesetters St Johnstone.
Morton stay seventh in the table and are still seeking a first win after drawing six of their seven games.
