Glentoran manager Eddie Patterson insisted Coleraine's goal should have been disallowed after Tuesday's Premiership draw at the Showgrounds.
Marcus Kane had fired the Glens into the lead just before half-time but Shane Jennings grabbed a 79th-minute equaliser for Oran Kearney's men.
"It was a blatant handball by Curtis Allen. The referee said it hit him in the stomach," said Patterson.
"The lads are gutted because they put in a fantastic display."
Despite having midfielder Richard Clarke limp off, Glentoran enjoyed a good first half and ended it with Kane striking a superb opener past home keeper Michael Doherty.
Coleraine came into it much more after the break with Elliott Morris making fine saves to deny substitute Jennings and defender David Ogilby.
Coleraine got their equaliser when Howard Beverland played the ball in and Jennings netted with a great finish.