The likes of Neymar and new Manchester City signing Gabriel Jesus were among the Brazil side, but despite seeing Mothobi Mvala sent off for the visitors, they couldn't find a breakthrough in Brasilia.
Brazil, who won silver at London 2012 but are yet to win an Olympic football gold, could have found themselves behind inside three minutes when Lebo Mothiba raced through on goal, but Weverton was alert to come out and deal with the danger.
Maphosa Modiba then fired narrowly wide as the visitors continued to keep their hosts on the back foot, much to the frustration of the crowd inside the stadium.
Brazil were forced to wait until just before the half-hour mark for their first meaningful effort on goal, and predictably it came from Neymar as his swerving strike was kept out by Itumeleng Khune.
Moments later they were in trouble again at the other end of the field as Mothiba beat Weverton to a corner, but he couldn't keep his header down and the home side once again survived.
Chances continued to arrive for both sides in the second half, with Dolly and Mothiba threatening for South Africa and Gabriel drawing a save from Khune in reply.
The hosts' hopes of getting off to a winning start were raised just before the hour mark, though, as Mvala was shown a second yellow card to leave South Africa with a numerical disadvantage for the final 30 minutes.
That sparked a period of Brazilian dominance as first Zeca drew a stop from Khune before Gabriel Jesus somehow hit the post when just three yards out in front of an open goal.
It was a hint that it would not be Brazil's day, and that feeling continued when Gabriel and Neymar both came close in quick succession soon afterwards.
In the end, South Africa survived the onslaught to come away with a draw, leaving the home fans frustrated following an inauspicious start to their bid for gold.