The Blues retained top spot in the Super Rugby Pacific table with a comprehensive 47-13 rout of New Zealand rivals the Highlanders, while the Brumbies claimed an extraordinary 31-24 win over the Canterbury Crusaders.
Hooker Kurt Eklund scored a brace of tries for the Blues, who ran in seven in all to snap the three-game winning streak of their rivals and cement their status as the team to beat in this year's competition.
The home quarter-finalists for this season have been set, with the Blues, Brumbies, Wellington Hurricanes and Waikato Chiefs all ensuring a top-four finish in the league phase.
The Brumbies secured a first win over the struggling Crusaders in 15 years following a dramatic 80th minute penalty try.
Chay Fihaki's penalty from inside his own half pulled the New Zealanders level with five minutes remaining after Tom Wright had led the home side to a comfortable 17-7 halftime lead with a pair of tries.
Brumbies flyhalf Noah Lolesio had a penalty to win it after the final hooter, but the ball struck the post and fell into the in-goal area.
Crusaders' Quinten Strange panicked under pressure and slapped the ball over the dead-ball line, leaving referee Ben O'Keeffe to award a penalty try - and the decisive seven points - to the home side.
"It was nervous, but we knew coming into this game that it was going to come down to the wire, especially against a quality Crusaders side," said the Brumbies captain Allan Alaalatoa.
"Probably a little bit of luck towards the end there and throughout the game we probably weren't clinical enough so some tough learnings, but it was awesome to get the win."
It is another blow to the Crusaders' play-off hopes as the defending champions are six points behind eighth-placed Fijian Drua with two rounds to play, and a fixture against the high-flying Blues next week.
Drua took another step towards the quarter-finals when captain Tevita Ikanivere scored a pair of tries to continue the strong home form of coach Mick Byrne's side and hand the Queensland Reds a 28-19 defeat in Suva.
The Reds had former Australia international Suliasi Vunivalu sent-off after 50 minutes following his second yellow card of the game.
"The team performed well today," said Ikanivere, who crossed the tryline twice.
"I challenged everybody this week to show up and I think they did. I just scored the tries because I was there at the right time."
The Western Force stayed in the hunt for a play-off place as they defeated New South Wales Waratahs 27-7 in Perth and move to within two points of Drua on the table.
Centre Bayley Kuenzle thought he had his second try in the final minute to earn his side a bonus-point, but he dropped the ball over the line and the Television Match Official ruled it out.
A 79th-minute penalty from Damian McKenzie ensured the Chiefs survived a late comeback from crisis-hit Melbourne Rebels in the rain on Friday to win 26-23 over their Australian hosts.
A pair of tries from Lachie Anderson pulled the Rebels back into contention with Nick Jooste's conversion levelling the scores, but McKenzie's successful penalty from under the posts ensured the Chiefs escaped with the win.
The Hurricanes were made to sweat before handing Moana Pasifika a 32-24 defeat with Peter Lakai's late try and a pair of penalties from Aidan Morgan helping to seal the win for the home side.