Both sides began nervously, and Riga were unable to build up any rhythm due to the absence of star smasher Mike Darwin, followed by an injury to Chris Nason.
Deeside took the first set 15-4, ,but Riga bit back to take the next three sets 15-12, 15-4 and 15-7,with the third set lasting only ten minutes.
Riga now travel to meet First Division Weymouth in the second round.
They face two home National League Division Two games at the weekend. when they take on relegated Estonians on Saturday evening and Roundwood on Sunday afternoon. both at Etone.
