Sydney: The Western Stormers can wrap up the South Africa conference and claim a home Super Rugby final with victory over their chief rivals Golden Lions this weekend.
The Stormers lead the Lions by three points and have only lost once against the Johannesburg-based team in their last 16 encounters.
While the Stormers are one win away from locking up the conference title, the race for the Australian conference has come down to a battle between defending champions NSW Waratahs and the ACT Brumbies with two regular season games remaining.
Both are locked on 42 points but the Waratahs hold the edge with games won as they try to reverse a losing three-game head-to-head run against the Central Cheetahs in Bloemfontein on Saturday.
Meanwhile, two-time winners Brumbies must beat Western Force in Perth on Friday to keep their title hopes alive.
Championship leaders Wellington Hurricanes will end the Otago Highlanders' remote hopes of winning the New Zealand conference title with victory at Napier on Friday.
The Stormers, who lost the 2010 Super Rugby final to the Northern Bulls, bowed out in the semi-finals in 2011 and 2012 and have missed the finals in the last two seasons.
But they appear to be running into form with four wins in their last five games, while the Lions are having a much improved season.
Under coach Johan Ackermann, the Lions have won nine of their 15 games, two better than last year and over the last 16 months have developed into one of South Africa's form teams.
South African flanker Jacques Potgieter has been named to return to the Waratahs' starting line-up for their crucial game with the Cheetahs.
In the only other change to the team that lost to the Lions last week, Matt Carraro has been preferred to Peter Betham as the replacement for suspended winger Rob Horne, who has been banned for three weeks for a lifting tackle.
Potgieter returns from a chest injury off the bench against the Lions and is a key inclusion for the penultimate round of the competition as the Waratahs look to secure a finals berth.
Blake Enever will replace injured lock Sam Carter for the Brumbies against the Western Force.
Carter has been ruled out for up to 12 weeks after sustaining medial knee ligament damage while playmaker Matt Toomua remains sidelined with an ankle strain.
The Highlanders, who have all but clinched a finals spot, have made six changes for their Kiwi derby with the Hurricanes.
Coach Jamie Joseph is resting key All Blacks Aaron and Ben Smith and Malakai Fekitoa, while Beauden Barrett is back at fly-half for the Hurricanes.
It will be Barrett's first game since injuring his knee on May 2, but coach Chris Boyd is giving blockbusting centre Ma'a Nonu the second of his two mandatory All Blacks rest weeks after he showed some signs of fatigue during last weekend's loss to the Crusaders.
If the Waikato Chiefs and Brumbies win this weekend, the Super Rugby season will be over a week early for the Canterbury Crusaders and Northern Bulls.
The Crusaders and Bulls are both six points out of the top-six play-off places with a maximum of 10 points left and are hoping for other results to go their way.
The seven-time champion Crusaders, who smashed the Hurricanes 35-18 last week, are away to the Blues in Auckland, while the Bulls must get past the Rebels in Melbourne.
The Chiefs, who slumped to a heavy 36-9 loss to the Highlanders last week, have key forwards Brodie Retallick and Liam Messam back from injury to face the Queensland Reds in Brisbane.
The Coastal Sharks have a bye.