It was the final act in a pulsating contest, one the Blues felt should have been an offside penalty as the Crusaders reversed the narrow loss they had against the Blues to start last year's series.
The Blues outscored their rivals two tries to one but new Crusaders five-eighths Tyler Bleyendaal punished the hosts' mistake rate and kicked the vital goals.
"I thought we scrambled well and in the end it was just one of those things," Blues skipper Keven Mealamu said.
"We will have a few things to work on and will be better next week."
So first blood went to the Crusaders, though their coach felt it had been a match where two strong sides cancelled each other out.
There had been a great deal of set- piece pressure and those disruptions caused the momentum to shift regularly.
"But it was everything you would expect from two good sides in the first game of the season, I thought," he added.
In the wash-up, the visitors' took the decision and probably showed a shade more composure at vital times.
The Blues began with a fury and precision which must have warmed the blood of most of the 32,000 who attended the opening game of the Super rugby season.
Rene Ranger broke half a dozen tackles with his initial touch and then Chris Lowrey delivered a hammer-hit as he led the defensive line.
Four minutes in and Lowrey had the opening try after he and Jerome Kaino charged down Dagg's clearing kick and Lowrey managed to force the ball close to the deadball line.
New Crusaders pivot Bleyendaal interrupted the onslaught with a penalty before debut Blues wing David Raikuna crossed in the eighth minute.
Once again Ranger was prominent, shooting down the middle of the park after Daniel Braid claimed a kickoff turnover.
Quick ruck ball was spun and Mealamu made the decisive pass into space for Raikuna to surge over.
It was a blistering start from the Blues, they looked menacing at every phase, sure in their execution and willing to shift the ball.
Questions about the Crusaders' response came after a short burst of rain hit the ground. They got their hands on the ball more and the Blues were forced to kick away what little possession they scrounged deep in their own half.
The Crusaders mixed up their attack, heading into midfield and then back down the blind where they stacked men and delivered indecision into the defences.
From one foray, burly centre Robbie Fruean had the overlap against several defenders and bolted past them as they hesitated.
"The Blues were awesome and held their line but that was just an opportunity and I took it," he said.
With Bleyendaal's conversion, the visitors suddenly had the lead inside the opening quarter.
It was a remarkable comeback in a frenetic opening but the pace slowed as a further Bleyendaal penalty was the only other scoring in the half.
There were moments though. Another Ranger breakaway was only shut down by Sean Maitland because of his extreme pace, and then Alby Mathewson knocked the ball on in a double tackle from a 5m scrum.
The Blues gambled on halftime, bypassing a shot at goal for a lineout but that roll of the dice failed when Rudi Wulf was penalised for obstruction in his search for the tryline.
After the break, new Blues five-eighths Michael Hobbs kicked two from three quick penalty attempts to give his side the lead once more.
With the last quarter to run, the Blues introduced Weepu. An opening touch was a bit ropey and the Blues were soon applauding Isaia Toeava more as the fullback made a try-saving tackle on Fruean.
The Crusaders worked a move from a scrum, Dagg sliced through and with Fruean and others in support, the Crusaders looked certain to score.
Toeava, however, drifted superbly on defence to halt the raid.
Crusaders
Try: R Fruean
Con: T Bleyendaal
Pens: Bleyendaal (4)
Blues
Tries: C Lowrey, D Raikuna
Con: M Hobbs
Pens: Hobbs (2)
