An offensively ruthless and defensively brilliant Crusaders have wrapped up their place in next week's Super Rugby final, beating the Chiefs 27-13 in Christchurch.

With their backs against the wall for much of Saturday's match, and barely one-third of possession, the Crusaders seized on every chance.

Midfielder-cum-winger Seta Tamanivalu bagged a clinical double, after earlier efforts by halfback Bryn Hall and Test stalwart Israel Dagg.

Without the ball, the Crusaders were equally impressive, holding a territorially dominant Chiefs outfit - with Damian McKenzie lurking from deep - to a single try, a late consolation to lock Brodie Retallick.

They'll look ahead to next weekend's final, with the location - at home or in Johannesburg - dependent on Sunday morning's other semi-final between the Lions and Hurricanes in South Africa.

The Chiefs will say goodbye to club mainstays Aaron Cruden, Tawera Kerr-Barlow and James Lowe, as well as coach Dave Rennie.

"We didn't have the ball much in that first half and the boys were definitely blowing," Crusaders skipper Sam Whitelock said.

"Full credit to the boys - they were hanging on tough out there.

"We knew that if we could weather that storm, we'd hopefully come over the top."

In stark contrast to last week's mutilation of the Highlanders, the Crusaders struggled to get the ball in the first half, with the Chiefs chancing their arm and enjoying three-quarters of possession.

Yet a long-distance Crusaders try drew first blood in the 16th minute, with Ryan Crotty offloading to Dagg, who slid Hall into space and across the line.

From that point, Scott Robertson's troops suffered under an avalanche of Chiefs possession and territory - yet, barring a pair of McKenzie penalty goals and a disallowed try, held on to halftime.

Dagg's fortuitous five-pointer quickly followed the break, capitalising on a clever poach from Richie Mo'unga, before Tamanivalu's double - one a barging effort and the other a smart finish on the right - put the match to bed.

"Rugby's a momentum game and we thought we created a lot of chances, had momentum at times, but you've got to give credit to the Crusaders," Cruden said.

"When it looked like we had them on the ropes, they were able to just do enough.

"We didn't give up. It certainly wasn't a lack of effort, but just wasn't to be."