Sportal.co.nz 10.Mar.2013Getty Images
In the scorching heat, the Blues were burnt by three-tries-to-two, much to the disappointment of the 25,112 Eden Park faithful.
A pair of tries, to wingers Lionel Mapoe and Akona Ndungane ensured the visitors were in front at half-time after Blues first-five Baden Kerr had put his side up with two penalty goals earlier in the match.
The second half saw a brief fightback from the Blues, who regained a one-point lead thanks to fullback Charles Piutau's try. But it was not to be as the Bulls hit back immediately with a try of their own to Arno Botha.
The result could have been different when Rene Ranger dotted down at the eleventh hour but a Morne Steyn penalty had already put the visitors too far ahead.
The four competition points gained through the win catapulted the 2010 champions into second place behind the Brumbies, who are the only other undefeated team after four rounds.
It was a sobering reality check for John Kirwan's Blues, who were flying high after upsetting the Hurricanes and Crusaders.
Kirwan's decision to introduce six debutants will certainly come under question. Taranaki's Waisake Naholo will want to forget a shaky afternoon on the big stage of Super Rugby.
It was no secret the Bulls would rely on their mammoth forward pack to gain dominance, but in the early exchanges John Kirwan's men looked rattled as they were outmuscled, then turned over possession at the breakdown.
A rolling maul from the ensuing lineout had them back pedalling at a rate of knots. This was text book stuff from the three-times Super Rugby champions.
Perhaps realising there was no way around the confrontational visitors, the Blues met them head on and diffused the next eight-man drive.
Preoccupied with the heated battle up front, the home side was guilty of over-committing in the middle and paid the price when wing Mapoe dotted down in the left corner.
That had the Blues down 6-8 after Kerr had negated an early Steyn penalty with two of his own.
His next act was not one he will be proud of, though.
A charged kick fell into opposition hands and set up the perfect opportunity for Nundangane to score. When Naholo missed the one-on-one assignment, the Bulls extended their lead to 15-6.
Naholo was again in the spotlight, or it was in his eyes, as he dropped a regulation kick in general play to end the half. A round of applause rang out as he caught his first of the second spell.
That was after Kerr reduced the deficit to 15-9 in the 44th minute.
The Blues rallied and entered opposition territory again but struggled with referee Garrett Williams' interpretation at the breakdown.
Nothing was to deny them on their next chance, though.
Bruising winger Frank Halai got within a metre of line and placed the ball promptly for a swooping passing play across to the left corner where Piutau was hardly bothered by two defending players as he scored.
The lead was short lived for the home side. The Bulls immediately got to within attacking territory, and in an almost identical move, flanker Botha was unopposed has he crossed the chalk.
The Blues' saying of: When it's on it's on, probably entered the mind of prop Angus Ta'avao as he ruined his chance to get his side five points closer with a dropped pass.
Rene Ranger's last-gasp try in the 76th minute would have been of more use had Steyn not pushed the Bulls nine points ahead with his second penalty earlier.
Tries: Piutau, Ranger
Pens: Kerr 3
Tries: Mapoe, Ndungane, Botha
Cons: Steyn 2
Pens: Steyn 3