The supporters were attempting to force coach Johan Neeskens to hand in his resignation.
Sundowns were beaten 2-1 by Maritzburg, their second defeat in the Premiership this season.
The Brazilians' fans are known for attempting to force club management to fire coaches, and it was no different at Lucas Moripe Stadium on Sunday.
Irate fans clashed with security personel as they tried to push down gates on the way to the dressing-room, and members of the SAPS were called in to beef up security at the stadium.
The fans were shouting "Neeskens must go" and chanting ex-Bafana Bafana coach Pitso Mosimane's name, saying that he must come and save the sinking ship at Chloorkop.
Supporters carried placards reading: "We are tired of Neeskens' promises, Pitso must rescue Sundowns."
Sundowns PRO Kabelo Mosito said he was not in a position to comment about the incident.
Mosimane has also been linked with move to Orlando Pirates, who have not scored in four matches under Augusto Palacios.