Viljoen finished with four wickets for 33, while Bernard Scholtz and Louis Klazinga claimed two wickets apiece.
Man of the match Snyman said the victory was the result of a team effort, with good partnerships through the innings.
"Our batsmen were backed up really well by the bowlers. They worked out the wicket well."
"Momentum is the biggest thing in a tournament like this, and a win first up is just what we wanted.”
Netherlands captain Borren was disappointed with the result after a strong opening performance against Uganda.
“We obviously didn't play to our usual standard. The team's batting performance was simply not good enough and we'll have to improve pretty quickly.”
Scores in brief:
At Bay Oval 2, Mount Maunganui, Tauranga, North Island
Namibia 253 for six in 50 overs (Gerrie Snyman 74, Christi Viljoen 46 not out, Craig Williams 36; Mudassar Bukhari 3-40, Michael Swart 2-44)
The Netherlands 162 all out in 36.5 overs (Michael Rippon 44 not out, Stephan Myburgh 40; Christi Viljoen 4-33, Bernard Scholtz 2-31, Louis Klazinga 2-36)
