Portsmouth's 23-year-old lightweight prospect Lucas Ballingall (13-1, 3KOs) was defeated on points away from home in Belarus on promoter Al Siesta's Kold Wars event.
Scores of 75-78, and 74-78 twice were awarded to hard-hitting Arslan Magomedov (4-1-1, 4KOs) on August 3.
The Russian had won all his fights by knockout until Ballingall took him the eight-round distance.
In other action on the night, London's Kingsley Egbunike (5-1-1, 1KO) forced favourite Sergei Shigashev (9-0-1, 4KOs) to a draw in their eight-round super-welterweight contest.
In the main event of the evening, Russian Ramzan Baysarov (11-1, 6KOs) defeated Austrian-born Brit Konrad Stemkowski (9-4).
Former Russian welterweight champion Aleksei Evchenko (19-13-1, 8KOs) prevailed on points over eight-rounds against former IBF Inter-Continental welterweight champion Victor Plotnikov (33-9, 15KOs).