All eyes will be on the clash at FNB Stadium this weekend as Pirates look to maintain their current advantage in the Betway Premiership title race, where they lead Sundowns by a solitary point having played one game more.
Mphela, who spent the bulk of his time at Chloorkop until switching to Naturena for an 18-month spell in 2014, could not hide his bias as he roots for The Brazilians to win a ninth consecutive title.
"I think both teams are on form; they have won their past few games, but like we always say, form doesn't matter when you go into the Soweto Derby. It's about pressure and pride on the day, and obviously the history of both teams," said Mphela.
"But I'll be a bit biased here because the other team has to win the league as well, so I'll go for a Chiefs win, 2-1."
Pressed on whether Sundowns' continued dominance is good for the league, the 41-year-old admitted that Pirates' challenge this season makes things interesting, while a new champion may not be a bad thing for the Premiership as a whole.
Having suffered a last-minute injury that kept him out of the previous Derby that the Bucs won 3-0, Mphela believes goalkeeper Brandon Petersen's presence could be crucial for Chiefs.
The debate is on regarding the favourite for the PSL Footballer of the Season award, with 'Killer' listing his top three nominees for the gong.
"My top three will be, obviously, Rele [Relebohile Mofokeng]; he must be there. I think he has been consistent. I mean, for a young boy to carry a team like Pirates on his own - I mean, not on his own; he's got other players around him-but you understand what I mean Rele will be my first choice."
"Then Khuliso Mudau; I think he had a good season. He started slow because of the issues he had with the team, and then [Iqraam] Rayners needs to be there because he has been consistent in front of goal, so I think those will be my top three. There are other youngsters that will fight for the Young Player of the Season award."