The Highlanders put the pressure on conference rivals the Crusaders after beating the Chiefs 29-25 at Forsyth Barr Stadium in Dunedin on Friday.
Defeat all but ends the Chiefs' hopes of defending their Super Rugby crown as they now sit six points off the Highlanders, with play-off rivals yet to play.
For the Highlanders meanwhile, they will hope the Hurricanes can do them a huge favour when they host the Crusaders in Wellington on Saturday.
The first-half score of 10-13 was a fair reflection of how things had panned out as the Chiefs were dominant, especially in the opening 25 minutes. However, the Highlanders did make a rod for their own back with sluggish clearing kicks and also unusually sloppy work from their back-three.
Such an area led to the first points of the game for Aaron Cruden as a clever hit from Tom Marshall on Lima Sopoaga after he had taken a high kick saw the home fly-half pounced upon at ruck time. Up stepped All Black number ten Cruden from distance as his penalty went over off the post.
The Highlanders at this point were getting little joy as errors cost them, this time the ball squirting out of their own scrum which led to the busy Bundee Aki being held up over the whitewash. It was clear that the Chiefs were using all their knockout experience.
One area the hosts were finding positives though was at the scrum where they won two penalties in the half, one leading to their first try. And what a try it was as Shaun Treeby's surge preceded Malakai Fekitoa busting tackles before Ben Smith fed Patrick Osborne.
With the simple extras the Highlanders were now 7-3 in front but it wouldn't last long as moments later Cruden's grubber down the short side saw the bounce evade Ben Smith, with Chiefs wing Dwayne Sweeney pouncing for a sobering try for the home supporters.
Just before the half-hour, Chiefs full-back Gareth Anscombe extended the lead to six points with a long-range effort after more good breakdown work from Aki. But that lead would soon be cut to three when the Highlanders' second scrum penalty saw Sopoaga make it 10-13.
Things would improve further soon after the break for the Highlanders when a maul penalty meant the scoreline was levelled by Sopoaga at thirteen apiece at Forsyth Barr Stadium.
And then came the sucker punch from the home side as after a period of sustained pressure from the Chiefs just fifteen metres out, a breakdown steal from hooker Brayden Mitchell saw the Highlanders counter and score from distance. It came via Fekitoa's run down the right wing before he found wing Richard Buckman who in turn put the ball back inside to Ben Smith, with Sopoaga's conversion making it 20-13 with 50 minutes played.
The Chiefs were now making changes as Brodie Retallick came off for Matt Symons while Augustine Pulu was replaced by Tawera Kerr-Barlow either side of Sopoaga knocking over another three points after a further replacement, Tim Nanai-Williams, failed to roll away.
It was then made clear that the impressive Retallick's withdrawal was down to international workload over June's Tests, with Aaron Smith's departure shocking their supporters, who were comforted by the sight of Sopoaga kicking three more from another scrum penalty.
The Chiefs would cut the scoreline to 26-18 when Nanai-Williams slipped Fumiaki Tanaka before crossing but the missed conversion looked to be key from Cruden when Highlanders replacement pivot Hayden Parker kicked a penalty to push the advantage over one score.
However, replacement Chiefs prop Josh Hohneck's powerful finish with four minutes remaining made for a tense finish but the Highlanders managed to hold on for the win.
Tries: Osborne, B Smith
Con: Sopoaga 2
Pen: Sopoaga 4, Parker
Tries: Sweeney, Nanai-Williams, Hohneck
Con: Cruden 2
Pen: Cruden, Anscombe
Highlanders: 15 Ben Smith, 14 Richard Buckman, 13 Malakai Fekitoa, 12 Shaun Treeby, 11 Patrick Osborne, 10 Lima Sopoaga, 9 Aaron Smith, 8 Nasi Manu, 7 Shane Christie, 6 Elliot Dixon, 5 Joe Wheeler, 4 Tom Franklin, 3 Ma'afu Fia, 2 Brayden Mitchell, 1 Kane Hames.
Replacements: 16 Ged Robinson, 17 Matias Diaz, 18 Chris King, 19 Josh Bekhuis, 20 Lee Allan, 21 Fumiaki Tanaka, 22 Hayden Parker, 23 Phil Burleigh.
Chiefs: 15 Gareth Anscombe, 14 Dwayne Sweeney, 13 Robbie Fruean, 12 Bundee Aki, 11 Tom Marshall, 10 Aaron Cruden (c), 9 Augustine Pulu, 8 Liam Squire, 7 Tanerau Latimer, 6 Liam Messam, 5 Brodie Retallick, 4 Michael Fitzgerald, 3 Ben Tameifuna, 2 Mahonri Schwalger, 1 Pauliasi Manu.
Replacements: 16 Nathan Harris, 17 Jamie Mackintosh, 18 Josh Hohneck, 19 Matt Symons, 20 Tevita Koloamatangi, 21 Tawera Kerr-Barlow, 22 Tim Nanai-Williams, 23 James Lowe.
Referee: Garratt Williamson (New Zealand)
Assistant referees: Kane McBride (New Zealand), Mike Lash (New Zealand)
Television match official: Chris Wratt (New Zealand)