Masandawana turned focus to the continent and handed starts to Brian Onyango, Mosa Lebusa in the absence of Rushine De Reuck and Mothobi Mvala.
Sundowns hit the front on nine minutes courtesy of Themba Zwane, leaving their counterparts with their work cut out earlier on in the contest.
The South African champions battled away following the latter exchanges of the clash, whilst Maniema Union slowly and slowly probed an all-out turnaround.
The outfit from the Democratic Republic of Congo got the equaliser shortly ahead of halftime as the Brazilians struggled to maintain their defensive shape.
Sundowns looked to restore their tally following the start of the second half, but Maniema held tight to perverse the small margin of the tie.
Fresh set of faces from the Brazilians in the middle of the second stanza saw Sibusiso Vilakazi and Sphelele Mkhulise introduced for Thabiso Kutumela and Pavol Safranko respectively.
With time running out, Sundowns did indeed go on to restore their lead through another finish from Zwane who in the process completed his brace.
The lead was cut short again as the home outfit grabbed the equaliser that in the end ruined the visitors chances of a first-leg victory ahead of next week's return-leg.
Sundowns: D.Onyango, Mudau, Lakay, B.Onyango, Lebusa, Jali, Coetzee, Zwane, Kutumela, Safranko, Shalulile.
Subs: Pieterse, Maluleka, Modiba, Morena, Mkhulise, Sirino, Domingo, Erasmus, Vilakazi.