The Crusaders have pulled a win from the Super Rugby fire for the third successive match, downing the Blues 33-24 in Christchurch to maintain their unbeaten start to the season.

Down 21-5 at the break, the Crusaders relied on their trademark set-piece ability and all-Test tight five to propel them to victory.

Pete Samu and Ben Funnell both scored on the back of driving mauls to give their side a sniff, before playmaker Mitch Hunt finished off a flowing multi-phase move to edge the Crusaders in front.

Reserve halfback Mitch Drummond then killed off the match with a minute to go after yet another clinical Crusaders scrum.

The Canterbury-based side won 14 from 15 lineouts and all seven scrums in their nine-point victory, sending them to the top of the New Zealand conference.

"It'd be quite nice if we started before halftime, but a win's a win," Crusaders skipper Sam Whitelock said.

Mediocre in last week's loss to the Highlanders, the Blues hit the ground running in the Garden City and showed plenty of attacking intent.

Patrick Tuipulotu fell inches short of barging over in the fourth minute, before the Blues turned on the razzle dazzle for their eighth-minute opener.

Skipping past three defenders, winger Matt Duffie gave Augustine Pulu the space he needed to slice through the Crusaders' left-edge defence and send George Moala over.

The Crusaders summarily hit back in the 24th minute through debutant Manasa Mataele, but further tries to the zippy Pulu and Moala put the Blues in control.

Ahead by 16 at the break, the Blues almost extended their lead when a rampaging Moala fell metres short of a hat-trick within two minutes of the restart.

But it was all downhill from there for Tana Umaga's men as, barring a Piers Francis penalty goal, they were kept silent for the second 40 minutes.

At the other end of the field, Samu and Funnell were getting the Crusaders' comeback under way against a rattled Blues defence.

Hunt crossed to put his side in front, before Drummond ended the contest.

"We just didn't come out swinging in that second 40. We wanted to play with width but we didn't quite get that right," Blues skipper James Parsons said.

"They're fighters - we knew that.

"The season's certainly not over. I know people are going to say that but, from within camp, we're still positive."