The Baby Manu recovered from a half-time deficit to overcome previously unbeaten Namibia 41-28 in Bucharest on to finish top of Pool A with three straight wins.
Fiji, meanwhile, maintained their perfect record in Pool B after scoring eight second half tries to seal a come from behind 53-26 victory over Canada.
The Baby Flying Fijians also trailed at half-time, and didn't take the lead until the 67th minute, but scored seven tries in the final 25 minutes to keep their promotion hopes alive.
