The Crusaders' relentless defence has given coach Scott Robertson a ticket back to the Super Rugby finals for his 100th game in charge despite spending 30 minutes playing with 14 men due to Pablo Matera.

In an evening where four cards were issued, Matera was responsible for three of them as he earned two yellows and a subsequent red in the hard-fought 20-7 win.

Matera's first sin bin was the result of ill-discipline from the Crusaders inside their 22 as the Chiefs struggled to convert their territory into anything but a whistle blow from referee Nic Berry.

Eventually Berry had enough and sent off Matera for the Crusaders' seventh penalty near their line after the Argentinian loosie didn't release the ball carrier.

His second yellow card just three minutes after he had returned to the pitch was for his shoulder making direct contact with Chiefs playmaker Bryn Gatland's head.

Although there were mitigating factors in the contact, Berry saw enough to issue another yellow and with it give Matera an early trip to the showers.

Woven in amongst the chaos was some silky play from both sides in challenging Christchurch conditions as the Crusaders manufactured a 20-7 lead at the break despite only controlling 30 percent of the possession and 43 percent of the territory in the first half.

Add on top of that their approximate 20 minutes with 14 men on the pitch and it starts to become clear how gritty their defence was - and how frustrated the Chiefs were getting.

Two significant blown chances in the first half will haunt the Waikato side heading into their offseason, especially the dropped ball inside the Crusaders' 22 that the hosts then ran all the way down the other end for an eventual 5m scrum and try to Cullen Grace.

Not only did it relieve all the pressure they had built in the last 10 minutes, but it gave the Christchurch faithful a reason to get fired up alongside a visibly pumped Sevu Reece.

The Chiefs managed to strike back with Angus Ta'avao while Matera was still serving his first card but a pinpoint skip pass from Richie Mo'unga allowed Grace to grab a brace just before halftime.

It was much the same for the second half as the Chiefs again set up camp inside the Crusaders' half but all the territory, possession and earned penalties meant nothing as they failed to find another hole in the armour.

In the end, the Crusaders made more than double the tackles of the Chiefs but in doing so showed why they're a dynasty to be reckoned with for either the Blues or Brumbies next week.

Because as the old saying goes defence wins championships, and next week Robertson and his resolute men will look to claim their fifth in five years.

Crusaders 20 [Cullen Grace 2 tries; Richie Mo'unga 2 con, 2 pen]

Chiefs 7 [Angus Ta'avao try, Bryn Gatland 1 con]

HT: 20-7