MORTON, who had lost five of their previous six home games this season, took the lead in the 14th minute. Stuart Greacen's cross was nodded down by Peter Weatherson for Erik Paartalu to volley home from ten yards for his first goal of the season.
Gregory Tade ought to have equalised 12 minutes later but shot rashly over from six yards after the home defence had failed to clear their lines at a corner.
Mainly, though, it was one-way traffic towards David McGurn's goal.
Rovers' problems increased in the 53rd minute when defender Grant Murray, who had been cautioned on the stroke of half-time for a foul on Brian Wake, was shown a second yellow card for a cynical foul on David van Zanten.
Manager John McGlynn immediately replaced striker Jonathan Russell with defender Craig Wedderburn but Morton took advantage of their numerical superiority to add a second goal in the 55th minute.
Weatherson was again the architect, splitting the new-look defence with a diagonal pass which Wake dispatched behind McGurn with a nonchalant right-foot drive from 15 yards.
They added a third on the hour when Greacen nodded a Jim McAlister corner towards goal and Wake stuck out a leg to force it home from point-blank range.
Weatherson got the goal his performance merited two minutes later, lashing the ball into the unguarded net after McGurn palmed Wake's driven cross into his path and he completed the scoring with a header from Ryan Kane's cross.
