As expected goalkeeper Itumeleng Khune's absence paved the return for Daniel Akpeyi, but forwards Samir Nurkovic and Leonardo Castro missed out through injury.
Following a passive start, the Amakhosi were nearly cut open from a penetrative delivery to Tiago Azulao but the defence came hurried back to stop the forward in his tracks.
However, the Amakhosi showed resolve on the half-hour mark to bag the front from a well-taken header by Eric Mathoho as the Angolan side failed to clear their lines from a corner-kick.
A second almost fell the Glamour Boys' way in the last ten minutes to halftime following a cross-cum shot on the far side of the area from Bernard Parker, but it was parried by Signori Antonio.
Chiefs threw numbers forward for a second right following the start of the second half, but Parker and Lazarous Kambole couldn't take the initiative up front.
Petro were left off the hook midway in the second stanza after Daniel Cardoso headed a probing ball from out wide against the upright and back into play.
Antonio was called to work a few moments later with a snap-shot from close-range by Happy Mashiane as the defence failed to cover their lines.
Chiefs coach Gavin HUnt introduced his first substitution in the latter periods in Siyabonga Ngezana, who replaced Mathoho.
The Amakhosi put the match beyond doubt when Mashiane sliced through the defence inside the last ten minutes to apply a solid finish.
Petro provided a late surge as the match headed towards conclusion, but it didn't trouble Akpeyi who gathered to steer the host to a maiden victory in Group C.
Chiefs: Akpeyi, Mathoho, Frosler, Cardoso, Zulu, Katsande, Ngcobo, Mashiane, Manyama, Kambole, Parker
Subs: Bvuma, Baccus, Blom, Lesako, Sasman, Matsheke, Ngezana