The Lanarkshire side took the lead after 16 minutes when teenager Andy Ryan cracked a low 15-yard angled drive on target and the ball was turned into his own net by luckless Peter Weatherson.
Two minutes later Morton were again the architects of their own downfall when Marc Smyth was caught in possession by Jon McShane, who produced a clinical finish from 12 yards. The points appeared secure in 51 minutes when another blunder by Smyth let McShane net. Accies’ fourth came when Simon Mensing lashed the ball home from 28 yards.
Hamilton were reduced to ten men when captain Alex Neil saw red for a second booking, sparking a Morton revival. Mensing put through his own goal in 78 minutes, Darren McGeough scored seven minutes later and Derek Young netted one minute from time.