Peter MacDonald's hat-trick against Airdrie United helped Morton cut Partick Thistle's lead at the top of the First Division to two points.
Allan Moore's men went ahead when MacDonald turned in Colin McMenamin's cross and the striker added a second with a low drive.
He completed his treble with a stunning strike and McMenamin netted a penalty.
Sean Lynch and Alan Cook pulled goals back for Airdrie but Marc Warren headed an own goal for Morton's fifth.
The hosts' penalty came when Grant Evans fouled Mark McLaughlin and the Airdrie player was sent off with 10 minutes remaining for a professional foul on Archie Campbell.
Thistle, who are not on league duty this weekend due to their involvement in Sunday's Challenge Cup final, now have a game in hand.
Bottom club Airdrie remain 10 points adrift with five games to play.
Morton: Gaston, Taggart, Reid (Wallace 88), Mark McLaughlin, Halsman, Wilkie (McDaid 89), Bachirou, Tidser, O'Brien, MacDonald (Campbell 66), McMenamin. Subs Not Used: Hutton, Graham.
Goals: MacDonald 5, 22, 60, McMenamin 69 pen, Warren 85 og.
Airdrie Utd: Robbie Thomson, O'Neil, Lamie (Warren 66), Buchanan, Evans, Bain (Cook 55), Hetherington, Lynch, McLaren, Coogans, Donnelly. Subs Not Used: Arthur, Barclay, Moore.
Sent Off: Evans (80). Booked: Hetherington, Lamie, Evans.
Goals: Lynch 70, Cook 73.
Ref: George Salmond