Playing away from their Eden Park fortress, the hosts outscored the South African visitors six tries to two at Albany's North Harbour Stadium.
The Blues captain James Parsons told Sky Sport he was pleased by the large crowd in Albany despite his side's recent results.
"We're extremely grateful. We obviously didn't get the result last week so gave them plenty of reason not to turn up," said Parsons.
"For them to turn up in numbers like this we're absolutely wrapped and also shows that bringing a game to QBE (stadium) is worthwhile."
In a clinical second-half the Blues ran in five tries after the break to turn a tight contest into a rout.
The Bulls did well to keep the score down to 7-7 at halftime before Matt Duffie touched down twice with replacements Ihaiha West and Matt Moulds also adding tries.
Winger Melani Nanai rounded off a sweeping move to blow the visitors away before the Pretoria-based Bulls managed a late consolation try through Rudy Paige after the final hooter.
The loss was the Bulls' fourth in five matches.