Leinster fended off a second-half comeback to beat Northampton 20-17 in the Champions Cup semi-final at Croke Park.
Leinster dropped from the top of the United Rugby Championship standings after losing 42-12 to the Stormers in Cape Town.
Prop Brok Harris will become the first player to reach 150 appearances for the Stormers in the URC clash with Leinster at DHL Stadium on Saturday.
Ruben van Heerden says the focus this week is attitude and intensity as the hardworking Stormers lock embraces the challenge of a massive clash with Leinster at DHL Stadium on Saturday.
The Lions took full advantage of going up against a weakened Leinster outfit at Ellis Park on Sunday, as they romped to a 44-12 URC victory.
The Lions are back in Johannesburg this weekend when they take on Irish giants Leinster in Round 14 of the United Rugby Championship.