Benni McCarthy's Cape Town City ensured a repeat of last year's final by beating Sundowns 4-2 on penalties at Lucas Moripe on Sunday after a 1-1 aggregate scoreline.
Cup holders SuperSport United edged Kaizer Chiefs 1-0 at FNB Stadium on Saturday to advance 3-2 on aggregate under the watch of Kaitano Tembo.
Mosimane says he would prefer to see Tembo win a trophy in what is his first season as a head coach, having recently been promoted from caretaker boss of Matsatsantsa.
"It's not about losing the match and having sour grapes," Mosimane said.
"As much as I wish him [McCarthy] the best and want him to win, I also want Kaitano, who has been with me for many years at SuperSport as my player, student - I also want him to win his first trophy.
"Because I want him to cement his position as SuperSport United head coach because the match is important to him.
"I can't win everything, other people have to win also. I will win next time, it's football."
It's been a tough spell for Downs, who also exited the CAF Champions League last week in the group stages.
Mosimane added: "It's not about winning and winning. You got to learn and let the team settle. I know supporters are little bit not happy but it's always good to wobble a little bit and come back.
The Brazilians next visit Golden Arrows in the league at Princess Magogo Stadium on September 19.