They picked up a yellow card late in the first half and it proved costly.
The Chiefs ran in two tries with the extra man to set up a 42-12 win in Hamilton last night.
The Highlanders’ playoff prospects are now held together only by an impossibly thin mathematical thread.
They also lost star winger Caleb Tangitau to a serious-looking knee injury in the final moments of the game.
It was the Chiefs’ 250th win and their ninth in a row against the Highlanders.
The loss has left the Dunedin-based team stranded in seventh place — one spot outside of the top six — with one round-robin match remaining.
That game is against competition front-runners the Hurricanes in Wellington.
They are toast.
And the Chiefs took a bite, scoring six tries.
The home side dominated the opening exchanges.
Loose forward Simon Parker made a monster tackle on halfback Adam Lennox to set up a turnover for the Chiefs.
They battered away, but the Highlanders’ defence held up.
When the visitors got their hands on the ball, they looked dangerous and their scrum was in the ascendancy.
They pounced. Lucas Casey, who had a strong game, launched himself from the base of said scrum from about 15m out. He toed first five Josh Jacomb for about 10 of those metres on his way to the opening try.
The Chiefs have some powerful ball carriers and they struck back. Lock Seuseu Naitao Ah Kuoi got a brilliant inside pass to Wallace Sititi, who finished a good team try.
The Highlanders had a further setback when lock Tomas Lavanini got 10 minutes for an early tackle.
The Chiefs capitalised. Ah Kuoi crashed over from close range and was about to get another.
Fullback Damian McKenzie ran the ball back from a clearance and sliced through. Ah Kuoi was on hand and dived over from the base of the ruck.
The Chiefs went into the break leading 21-7.
Highlanders coach Jamie Joseph made a tactical change during the break.
Taine Robinson replaced Cameron Millar at first five.
But it was the forwards who almost created some magic. They poured through a lineout and Casey got over the chalk.
Sititi got an arm around him, though, and held the ball up.
Not long after that halfback Xavier Roe threw a dummy and ran in untouched to score the Chiefs’ fourth try.
The Highlanders will have to watch the replay to figure out what happened there.
Jacob Ratumaitavuki-Kneepkens got on the end of the chain and scored with about 20 minutes left to spark some hope.
But the Chiefs put the game to bed when replacement hooker Brodie McAlister drove over from a lineout.
Super Rugby
The scores
Chiefs 42
Seuseu Naitao Ah Kuoi 2, Wallace Sititi, Xavier Roe, Brodie McAlister, Kyle Brown tries; Damian McKenzie 4 con, Josh Jacomb 2 con
Highlanders 12
Lucas Casey, Jacob Ratumaitavuki-Kneepkens tries; Cameron Millar con
Halftime: 21-7
