Galway's Adam Hession suffered a narrow loss to Russian Eduard Savvin in his last-32 bout in the AIBA World Championships in Belgrade.
The 21-year-old featherweight, who won silver at the European U22s this summer, was edged out on a 4-1 split decision, with four of the five judges scoring the fight 29-28.
The Irishman's corner and many of those observing felt he'd done enough to win but the judges thought otherwise and Savvin progresses to the last-16.
The loss continues what has been a miserable world championships for Ireland, with five defeats from five bouts thus far.
Ireland have sent an inexperienced squad of seven to the championships, after none of the male Olympians who were in action in Tokyo competed in last month's national elites.
Before Hession, Eugene McKeever, Sean Mari and Brandon McCarthy and John Paul Hale were all eliminated their first bouts.
Rickey Nesbitt (48kg) and Keylan Cassidy (80kg) are the last two Irish fighters standing, both in action on Saturday.