Bellahcene became the 2012 Algerian chess champion at the age of 14, being the youngest to win this title. In the 2013 and 2017 African Individual Chess Championships, he represented Algeria and finished fifth each time. He also participated in the 2012, 2014, and 2016 Chess Olympiads as part of the Algerian national team.
However, his career has been marred with cheating allegations. In 2012, during the World Junior Chess Championship, he was accused of cheating and was disqualified. Following the incident, the Algerian Chess Federation suspended him for two years from participating in any competition.