Colin took Uranchimeg by surprise in the first round and fought well, despite slipping 4-3 behind.
The Mongolian was finding it difficult to implement his gameplan on the Mauritian, who was boxing bravely.
Uranchimeg led by two points heading into the final round, forcing Colin to force the issue.
That brought him right within Uranchimeg's range and he showed some fast hands to rack up some points and put the contest out of doubt.
The judges scored the bout 20-12 in favour of Uranchimeg.