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.
Defending champions Tuks continued their unbeaten run in the Varsity Cup with a 26-16 victory over UCT at the Green Mile.
Just two log points separate the top four teams in the Varsity Cup ahead of Monday's matches.
Maties bounced back from a disappointing start to the Varsity Cup to win in Potchefstroom. Charl de Villiers, Johnny Kotze, Robert du Preez and Louis Jordaan all scored for the Stellenbosch team.