According to the Football441 website, the 38-year-old, who worked under Bafana coach Gordon Igesund during their time together at Santos, was recently appointed as the country's new national coach and is eyeing a place in the COSAFA Cup semi-finals.
The Namibians have twice got the better of their southern neighbours in their two previous meetings at the competition and they will be feeling confident of making it a third-time lucky as they prepare to face a weakened South Africa squad.
Igesund had initially elected to announce a strong squad for the quarter-final clash, but following a spate of withdrawals of a number of key players, he has been forced to rethink his plans.
And Mannetti feels his side has a real chance of recording a positive result on Saturday, saying: "Anything can happen when Namibia face South Africa because it is always an emotional occasion.
"We have defied the odds to shock Bafana Bafana several times in the COSAFA Cup and I would love to get one over my former boss Gordon."