Argentina will finish second in the pool and face a quarter-final against the winners of the Pool D game between Ireland and France to be played later in Cardiff.
Namibia can do no better than finish bottom of the pool, but that does not mean there will not be some edge to a fixture that both sides are keen to win for very different reasons.
Argentina coach Daniel Hourcade had made 11 changes as he looks to include players who have been on the fringes of selection in the tournament so far.
He wants to keep his full squad match fit ahead of the knockout stages and has been handed the chance to do so against the lowest ranked side in the competition.
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The experienced Juan Martin Hernandez, one of the standouts of the Pumas side that reached the 2007 semi-finals, has been handed a rare outing in the number 10 shirt.
The 33-year-old will marshal a backline featuring another veteran of the 2007 campaign, left winger Horacio Agulla.
"It's good that all the players are okay and we believe it's good to give the others some minutes, we have a very even squad," Hourcade said.
"We want to finish the group phase well, improve defensive aspects because we weren't aggressive enough (last time out against Tonga) and our finishing because we had some good movements but in some of them we didn't finish well.”
Namibia are seeking a first World Cup win at the 19th attempt and have shown themselves to be a far more competitive side in this year’s competition.
They go into this final fixture without inspirational captain Jacques Burger, ruled out after picking up a concussion early in their narrow 17-16 loss to Georgia, and outstanding number eight Renaldo Bothma, who is suspended.
"For us it is important to back ourselves and make our country proud,” Namibia captain Rohan Kitshoff said.
“I think we’ve become renowned at this World Cup for showing guts and for fighting to the end. You can maybe doubt our ability but you can never doubt our character.”
(Editing by Ed Osmond)
