The Ivorian has struggled since joining Celtic nearly 2 years ago.
The Bhoys will now face Aberdeen in the final at the start of December after the Dons defeated Old Firm rivals Rangers in their semi-final.
The Ivorian kept his place in the side from the team that lost to RB Leipzig in the Europa League on Thursday night. He has been called in to replace injured captain Scott Brown but his game yesterday did not last long.
Kouassi, who had an uncomfortable exchange with Hearts forward Steven MacLean in the first-half, later limped out of the action in the 26th minute.
It is certainly a blow for the Celtic man, whose career at the club looked over in the summer. As reported by the Daily Record, the Ivorian was told to find a new club on deadline day after Celtic snapped up Youssouf Mulumbu.
Kouassi had played just 11 times in the Scottish top-flight before the start of the current season and Celtic fans have never got to see him at his best.
One of the reasons for his struggles in Glasgow has been due to his injury and fitness troubles, so it is no surprise that he has limped out of action once again.