Jeff Monson knocked out in Christmas Day fight (VIDEO)
The taller and faster Nua circled Monson at the start of their fight, testing the Russian's defenses with sharp left jabs. With no offence coming from Monson, Nua unleashed a vicious right that hit Monson on the side of his head and knocked him down.
Monson, nicknamed the 'Snowman', has now lost five of his last eight fights and has a 59-25-1 record.
Monson recently received Russian citizenship, following in the footsteps of legendary boxer Roy Jones Jr, who was also given a Russian passport earlier this year.