Maritzburg will host the newly-crowned MTN8 champions tonight at Harry Gwala Stadium, with kick-off scheduled at 20h00.
Mngonyama couldn't break through at Sundowns but was a first team regular in his three years with United, notably winning the club's Player of the Season prize in 2014/15 after helping them finish in the top eight for the time in their history under then-coach Steve Komphela.
The 25-year-old continued to feature under Roger de Sa and current Maritzburg coach Fadlu Davids, who he still holds in high regard.
"To be honest with you, coach Fadlu helped my game. I am what I am today because of him. He played a massive role," Mngonyama tells snl24.com/kickoff.
"I'll never forget what he did and wherever I'm going I'll say he did something good for me. I still want to grow as a player and continue to do what I'm doing.
"Also Harry Gwala Stadium will always be a home for me and it holds great memories for me. But now I'm on the other side and I have to do the job for City.
"The job is not done and I'll keep on pushing because I don't think you have a limit in football, so I'm that kind of person."
