Tembo is currently preparing his side for the MTN8 decider against Cape Town City at Moses Mabhida Stadium in Durban on Saturday.
Matsatsantsa won the competition last year when Eric Tinkler was in charge of the team.
"I am a bit chilled. Because of the kind of person I am, I don't really show a lot of emotions," Tembo said when asked if he has had sleepless nights ahead of the high-stakes encounter.
"I know it's an important game for us and for me as well, but what is important for me is the club. The club always comes first.
"I can only thank the board led by Khulu Sibiya and the CEO Stan Matthews for giving me this opportunity to lead the team. I know it's not easy.
"For them showing confidence in me that I can take the responsibility at such a big club is humbling.
"I can only reward them if we can go all the way and win the final."
Tembo was a long-serving assistant coach at United before taking over the reins in March on an interim basis following the departure of Tinkler.
He was later tasked with leading the club on a full-time basis in the off-season.