Five teams are in the running for the remaining three semi-final spots in the Varsity Cup.
The visitors scored three tries to claim a comfortable 24-8 win in Johannesburg.
The log-leaders ground out a 16-8 win in the Potchefstroom rain.
There were wins for NMMU, Maties, Pukke and UCT in round six of the Varsity Cup on Monday.
Monday's matches will have a major bearing on which teams make the Varsity Cup play-offs.
The visitors' good start to the match saw them emerge worthy victors.
The Madibaz had to work hard for a win in pouring rain.
Pukke, NMMU and UCT were all victorious in round five of the Varsity Cup on Monday, while Maties and Shimlas were deadlocked.
Top spot in the Varsity Cup will be on the line when defending champions Tuks host Pukke on Monday.