Sportal.co.nz 01.Mar.2013Getty Images
The home side overcame a shaky start, and the flawless kicking of Dan Carter, in the first half thanks to two tries by star wing Frank Halai that ensured they held a healthy 20-12 lead at the break.
Many would have expected more from the seven-time champions, who closed the gap to five points after half-time through Carter's fifth penalty goal, but they could not stop the spirited Blues and two more second-half tries ultimately sealed their fate.
The win saw Sir John Kirwan's men remain at the top of the New Zealand conference on 10 points.
The Blues dominated most of the match but could not escape the chasing Crusaders pack, which remained firmly in the hunt until Daniel Braid scored in the latter stages of the match.
France-bound centre Rene Ranger excelled in his battle with another potential All Blacks midfielder in Robbie Fruean.
The Blues pack was solid, and when a Callum Retallick break got them to within a metre of the line they were in position to land the first real blow of the match.
Preoccupied with the fierce trench battle, the Crusaders found themselves short on the blindside and the vision of halfback Piri Weepu kicked in as he threw a looping pass over two defenders to find Steven Luatua, who fell forward to beat Israel Dagg across the line.
Weepu would have rued two failed penalty shots at goal as the home side had just eight points to show for their dominant possession (70 percent).
But their work soon paid off as a stunning six-minute period saw Halai cross for two scintillating tries for a 14-point advantage.
However, Carter ensured the visitors remained in the contest with a penalty goal either side of the half-time break.
Crusaders coach Todd Blackadder would have wanted to turn things around quickly for his side, who looked like they had suffered from consecutive bye weeks that started their season.
And for a moment it looked like the Crusaders were returning to their expansive best with a number of raids that fell just short of the line.
However, after Braid muscled his way over to restore the Blues' lead to 25-15 in the final quarter, things were looking bleak for the visitors.
A searing burst down the left flank by winger George Moala had the fans on their feet and finally put the Crusaders out of their misery as the Blues cruised home by 19 points.
Tries: Luatua, Halai 2, Braid, Moala
Cons: Weepu 2
Pens: Carter 5