Smith stars for Highlanders
The Highlanders displayed their best form of the season to upset the Blues 38-28 in Dunedin.
The home side achieved only their second win in 13 Super Rugby matches this season, building a 29-7 lead by half-time and doing enough thereafter.
Tries from Ben Smith (two), Tamati Ellison and Hosea Gear set up the victory, with Colin Slade and Hayden Parker kicking the rest of their points.
Waisake Naholo, Rene Ranger, Steven Luatua and Luke Braid crossed for the Blues.
The Queensland Reds kept their finals hopes alive with a 33-20 win over the Melbourne Rebels in an intense encounter at Suncorp Stadium. The Reds outscored their opponents 20-3 in the second half to snatch a memorable victory.
The Stormers got the better of the Southern Kings in a hard-fought 19-11 victory in Cape Town.
Deon Fourie scored the hosts' only try of the contest, while 14 points from the boot of Joe Pietersen ultimately proved the difference on a wet afternoon at Newlands.
The Kings crossed for an unconverted Wimpie van der Walt try in the dying minutes, while George Whitehead weighed in with a brace of penalties.
The Bulls survived a late fightback to consolidate their place as the leading South African franchise in the Super 15 with victory over the Cheetahs in Bloemfontein.
Both teams scored three tries but it was the boot of Morne Steyn which saw the visitors from Pretoria over the line, with the fly-half kicking 15 points. The win lifts the Bulls eight points clear of their rivals in the South African Conference standings and with a game in hand.