The Bulls secured a top-two finish in the United Rugby Championship (URC) following a 26-14 bonus-point win over the Sharks in Durban.
The Stormers claimed a 29-24 victory over the Lions despite playing almost half the game with 14-men in Cape Town on Saturday.
Leinster boosted their hopes of a top-two finish in the BKT United Rugby Championship with a 33-7 bonus point win over Connacht at the RDS Arena.
The Bulls have named a fully loaded team for Saturday's final regular game of the URC season against the Sharks, with a chance to finish top of the table on the line.
The Stormers will be playing for something more in their last league match of the season against Lions at DHL Stadium, says head coach John Dobson.
The Lions stayed alive in the United Rugby Championship (URC) after a shock 44-21 victory over the Glasgow Warriors at Ellis Park on Saturday.