Ireland's bowlers starred as Simi Singh (three for 25), Mark Adair (two for nine), Boyd Rankin (two for 17) and Gareth Delany (two for 23) all chipped in to ensure a modest total was defended – Namibia falling short of their target of 136 by 27 runs.
It was the Irish batsmen who lost six wickets for 29 runs in the opening innings to give Namibia strong hopes of ending up victorious, the medium pace of JJ Smit (three for 19) and Craig Williams (three for 34) ensuring Ireland's batsmen could never really settle despite the best efforts of Andy Balbirnie's 46.
Ten balls into the reply and Namibia lost Nikolaas Davin before falling to 20 for three inside the Powerplay as Singh and Delany's spin strangled Gerhard Erasmus' side into submission, his 51 the only score of note and the only innings to go at more than a run-a-ball – Namibia eventually bowled out for 108 in 18.2 overs.
Ireland captain Gary Wilson said: "I am not sure we were at our complete best through the whole tournament, but that is probably what you are going to get from us at the moment. We are a very inexperienced right the way through the team.
"One day we will be a good side and another day we will be up and down and we have shown that through the tournament, we have won five and lost three and that is reflective of why we are in the third place play-off.
"We were probably not at our best today but it was a pleasing enough performance.
"I think we have come a fair way as a team, we did not rock up here and think this was going to be easy. But we can be satisfied with what we have done, we have qualified for the World Cup, but our goal when we came here was to win the tournament."
Namibia captain Gerhard Erasmus said: "When we had the winning streak of four games in a row, that is when I felt we could look at all 11 players on field and see the competing nature in their eyes, that is the one thing that stands out for me.
"Going forward we need to broaden the depth of our squads and that is always a challenge in Namibia and we need to get more competition going.
"If we can do that in the next 12 months then the quality of our performances will go up and it will be a real tussle to get into the 15-man squad, not only to go to the World Cup but also into the team."