Following a goalless first half, Sundowns took the lead in the 66th minute when Iqraam Rayners scored from a counter-attack by goalkeeper Ronwen Williams.
But the hosts hit back after eight minutes through captain Mohamed Hrimat who connected a Youseef El Fahli cross.
It ended 1-1 at the Stade Ben Ahmed El Abdi with Masandawana failing to collect maximum points for a second straight Champions League outing.