New Zealand's Chiefs became the first team to qualify for the top-six playoffs after they beat the Highlanders and consolidated their lead at the top of the Super Rugby standings.
South Africa's Stormers also remained on course for a top-two finish and with it a bye into the second week of the finals later this month after shading the Lions in a South African derby in Cape Town.
Elsewhere in the scramble for the remaining four playoff spots, the Brumbies maintained their five-point lead at the top of the Australian conference with a 28-17 victory over Western Force in Perth.
The Bulls are fourth on points differential after a 40-24 win over the Cheetahs in Pretoria to lie four points adrift of the Stormers in the South African conference.
Seven-time Super Rugby champions the Crusaders had a setback at home when they were overhauled by fellow Kiwis the Hurricanes 23-22 and fall 10 points behind the Chiefs in the New Zealand conference with two games left.
Inspired by two tries from skipper Conrad Smith, the Hurricanes upset the Crusaders in a gripping game where the lead changed five times.
The Hurricanes victory handed the New Zealand conference title to the Chiefs as it meant that the Crusaders are now unable to overtake the Chiefs.
The Hurricanes occupy sixth place on points differential ahead of defending champions the Reds and South Africa's Sharks.
The Reds accounted for the Rebels 32-17 in Melbourne, while the Sharks had a bye along with the Waratahs and Blues this weekend.
The Reds clinched the extra point with a try by replacement back Nick Frisby six minutes from time after the Rebels had fought back to trail 27-17.
All Blacks fly-half Aaron Cruden proved the difference as the Chiefs dimmed the Highlanders' playoff hopes with a 27-21 win in Dunedin.
In the first match back after a three-week break for international fixtures, both sides scored two tries apiece but Cruden's five penalties proved the crucial factor in a tightly-contested New Zealand derby.
The Chiefs are in the box seat to finish top of the New Zealand conference ahead of two tough final two regular season matches against the Crusaders and Hurricanes.
At Newlands, Canadian international Jebb Sinclair came off the bench to score a crucial try as the Stormers weathered the Lions 27-17 in a rugged encounter.
The Stormers were under severe pressure against the southern hemisphere competition's bottom team as they clung to a three-point lead with 12 minutes to go before Sinclair scored a try in the corner to seal it.
The Brumbies maintained their winning ways with a bonus-point win over the Force, who mounted a spirited second-half fightback.
The Brumbies looked set for a comfortable win when they led 22-0 at half-time in retiring Force veteran Nathan Sharpe's farewell home and his 161st Super Rugby match.
But the Force rallied to slice the margin to eight points before Jake White's Brumbies steadied through a Zack Holmes penalty.
The Bulls scored six tries and then switched off against the Cheetahs at Loftus Versfeld.
A rout had seemed on the cards when left-wing Bjorn Basson crossed for his ninth try of the season 18 minutes into the second half and fly-half Morne Steyn converted to put the three-time champions 40 points ahead.
But instead of surrendering, the mid-table Cheetahs ran in four tries for a bonus point that gave the final scoreline more respectability.