Bradley Pryce lost an unanimous points decision against Sergey Rabchenko for the vacant WBA inter-continental light-middleweight title on Friday.
Unbeaten 25-year-old Belarusian Rabchenko had not gone beyond six rounds in his previous 16 fights but dominated the early stages.
Former Commonwealth champion Pryce, 30, came back strongly and marked Rabchenko with good counters in the 11th round.
But the judges scored the fight 112-117, 112-116, 113-116 to Rabchenko.
The defeat at the Deeside Leisure Centre in Queensferry means Welshman Pryce, who lost his Commonwealth belt to Matthew Hall in March 2009, has now lost four of his last eight bouts and his overall record falls to 31-10-0.