Sydney - Super 14 surprise package the Reds are looking to add the Stormers to their list of top scalps this season in a top-four clash this weekend.
The Reds have already toppled the top two sides, the Crusaders and Bulls, and have the chance to make it a treble against the third-placed Stormers in Brisbane on Friday.
The once-maligned Reds have been a major talking point since their pulsating 19-12 victory over the Bulls at home last week, dislodging the defending champions from the top of the southern hemisphere provincial championship table.
The Reds, rejuvenated under the coaching of Ewen McKenzie, have broken into the top four for the first time since 2001 and begin a difficult run into the playoffs with matches to come against the Brumbies, Hurricanes and Highlanders.
The in-form Stormers, who have conquered the Blues and Chiefs in New Zealand in recent weeks, have won six games straight against the Reds, with the Reds' last win coming in Cape Town in 2003.
"This is the fifth South African side we'll have faced in as many weeks and each of their last four had particular strengths," McKenzie said.
"The Stormers combine elements of all four of those, so Friday is a bit like a final exam for all the work we've done over the past four weekends."
The Stormers are expecting the unexpected against the attacking Reds, who are a different proposition from in the previous six under-achieving seasons.
"They are always trying funny things, like all Australian teams," Stormers forwards coach Matt Proudfoot said.
"We saw in the Bulls game that they also look to mix it up in the lineouts. Their physicality and desire has impressed me."
The seven-time Super rugby champions Crusaders are in Perth to take on third-last Force on Friday on their way to South Africa for two testing games against the Stormers and Bulls.
All Blacks Daniel Carter, Brad Thorn and Kieran Read are back to bolster the Crusaders, wary about the Force, who have twice slugged out 23-23 draws in their five meetings.
Although it has been a disappointing season for the Force, they have always found something extra for the Crusaders in Perth and it is a match Todd Blackadder's men must win before their tough South African leg.
The second-placed Bulls have the best current home winning record of 16 consecutive matches in Pretoria and will be looking to stretch that against the last-placed Lions on Saturday.
The Bulls returned home this week after an Australasian tour that yielded two wins, two defeats, and 10 competition points and they want to bounce back from their upset loss to the Reds.
Bulls ace scrumhalf Fourie du Preez will be on the bench against the Lions with a shoulder niggle and swaps places with fellow Springbok Heini Adams.
A fierce Australian derby is in prospect with the fifth-placed Waratahs against the sixth-placed Brumbies in Sydney on Saturday.
The Brumbies' season is on a knife edge after they crashed at home to the Hurricanes last week and another loss here will make the playoffs a difficult objective.
The Waratahs have won eight times against the Brumbies, with the two-time champions prevailing in seven and their last win in Sydney coming in 2002.
In the weekend's remaining games, the Chiefs host the Cheetahs, the Highlanders take on the Hurricanes in Dunedin and the Sharks have home advantage against the Blues in Durban.