The Absa Premiership giants will collide in the semi-finals of the event in Windhoek on Saturday, with the victor facing either Tigers FC or African Stars in the title decider on Sunday.
Downs are targeting a hat-trick of triumphs at the annual pre-season showpiece.
"We have a game in Namibia, Dr Hage Geingob, the president of Namibia cup," says Mosimane.
"It's our third year we play. We have won it twice, we would like to win it for a third time and keep the trophy."
Mosimane expects a test from Pirates, who are smarting from a 2-0 loss to Kaizer Chiefs in the Carling Black Label Champion Cup this past weekend.
"They have really strengthened the team, from goalkeeper coach to head coach and even the physical trainer. It's a revamped team. They have made a big overhaul in terms of personnel, players coming in. So it will be a big game against Pirates."
He adds: "We know it's going to be difficult, we have to play Bangaly, Ricardo, Lucky, 'Vila' and the other guys that have not been playing."