Skipper Grant Gillespie’s late penalty handed Morton a cinch Scottish Championship victory at Inverness.
Gillespie struck five minutes from time after Wallace Duffy had been penalised for handling in the area to secure a 1-0 win.
In a cagey start, Caley Thistle had the better of it with Steven Boyd and Roddy MacGregor threatening.
However in the meantime, they had been forced to make a change when Austin Samuels limped off to be replaced by Nathan Shaw with just 24 minutes played.
Keeper Mark Ridgers had to claw away Jaze Kabia’s volley five minutes before the break as the visitors responded.
MacGregor might have settled a tight contest with an 83rd-minute header which flew just too high, but it was Morton who eventually broke the deadlock when Duffy was adjudged to have handled and Gillespie made no mistake from the spot.