The continental cup winners were held to a goalless draw by the Angolan Girabola league leaders at the Estadio Nacional da Tundavala last week.
They resume hostilities at Loftus Versfeld where Morena expects Sundowns to put in a commanding display and win the tie outright.
A draw would see the match decided by a penalty shoot-out.
Speaking ahead of the game, an upbeat Morena said in the Citizen: "As a team, it's something we take as a responsibility and believe in it (defending the CAF title).
"We can and we're willing to do it because we have done it at home in the PSL (Premier Soccer League).
"We have the experience of winning and what happens, we know teams will come all out against us.
“But playing on home soil will be different and we're going to give everything and that's the most important on the pitch.”
Orlando Pirates breezed into the CAF Champions League group stage after a dominant 4-0 victory over Namibian side African Stars at the Orlando Stadium to secure a 5-0 aggregate victory.
Mamelodi Sundowns have been eliminated from the CAF Champions League by Angolan Girabola league leaders Wiliete SC on away goals.
African Stars head coach Gerald Guther says his side will "leave everything on the field," in their crucial CAF Champions League qualifier with Orlando Pirates on Friday night.
Orlando Pirates will be looking to progress to the CAF Champions League group phase when they face African Stars in their second leg clash at Orlando Amstel Arena on Friday.
