The lethal forward joined the Algerian giants on a four-and-a-half-year deal from Asante Kotoko after an explosive half a season with the Porcupine Warriors.
The one time capped Black Stars player met his new teammates on Thursday and was involved in practice for the first time.
Opoku netted 9 goals in 16 games for Asante Kotoko to attract the Algerian to pay about $500,000 for the 21-year-old.
The prolific attacker is expected to replicate that form in Algeria as USM Algers aim to win the league.
