Trailing to Chile, Namibia finally prevailed 28-26 on Saturday in Valparaiso (north-west), in a match to prepare for the Rugby World Cup in France (September 8-October 28).
The Namibians, who conceded three tries in the first half, trailed by 12 points at the break (19-7), but turned the match around by scoring three tries of their own late on.
Namibia, the second African nation along with South Africa (reigning world champions) to compete at the World Cup, are in Pool A alongside New Zealand, hosts France, Italy and Uruguay.
Chile, meanwhile, will be taking part in a Rugby World Cup for the first time. It is in Pool D alongside Argentina, Japan, Samoa and England.