Peter MacDonald's second-half penalty proved to be the winner as Morton triumphed at home against Livingston in the First Division.
Michael Tidser's 25-yard short put the home side ahead after nine minutes.
But Iain Russell levelled from the penalty spot after Paul Di Giacomo hauled down Jason Talbot.
Morton re-established the lead nine minutes later when MacDonald converted from 12 yards after Tidser had been fouled by David Sinclair.
Morton: Stewart, McCann (Weatherson 68), Forsyth, Evans, McCaffrey, Tidser,Di Giacomo, Bachirou, MacDonald, Jackson (Campbell 65), O'Brien (McGeouch 69). Subs Not Used: Deans, Little.
Sent Off: McCaffrey (87). Booked: McCann, McCaffrey.
Goals: Tidser 9, MacDonald 64 pen.
Livingston: McNeil, Brown, Talbot, Sinclair (Boulding 79), Craig Barr, Watson, Fox, Keaghan Jacobs, Deuchar, Russell, Bobby Barr (Kyle Jacobs 84). Subs Not Used: Jamieson, McNulty, Travis.
Goals: Russell 55 pen.
Ref: Brian Winter