George Moala's try, after a sustained, clinical build-up, put the Blues ahead with 12 minutes remaining and Ihaia West's conversion, which put the margin past three points, was important. The breakthrough came after a fair amount of pressure from the Bulls, and in the absence of loose forward Luatua - with lock Josh Bekhuis also flat on his back receiving treatment.
It was a good reward, with Blake Gibson looking good as Luatua's replacement, and Francis Saili taking the right option and spearing a break near the prone Bekhuis.
Saili had a chance to score a try which would have sealed it, but his hands let him down. However, his spot tackle with two minutes remaining which earned his side a penalty was crucial.
Poor Marcel van der Merwe. The Bulls tighthead prop had a try ruled out in the opening minutes due to obstruction by Phillip van der Merwe on Akira Ioane and was then bamboozled by the pace and swerve of Blues fullback Lolagi Visinia, who went over from 40m.
Visinia's run showed what a sense of purpose can do and a few of his teammates began to follow suit. Second-five Moala, after a sketchy start, bulldozed defenders at will and even little halfback Jamison Gibson-Park was making gains up the middle.
They looked a chance to score every time they got into the Bulls half, but unfortunately for them the reverse was true too. After surviving that early scare when van der Merwe's try was ruled out by the television match official, there was no doubt about the one scored by Jan Serfontein, the second-five going over thanks to Handre Pollard's assistance.
There is nothing mysterious about the Bulls, who rest their entire game squarely on a tripod of scrum, lineout and rolling maul. With Victor Matfield and Phillip van der Merwe in the second row, plus the massive Pierre Spies at No8, the Bulls had a set piece weapon almost guaranteed to get results.
Serfontein's second try came from a scrum on halfway, and, while the second-five's pass to left wing Bjorn Basson looked forward in the build-up, it wasn't worth another viewing according to referee Mike Fraser.
In the end it didn't matter. A memorable week which threatened to tear the Blues apart ended with the players looking more united than ever.
Blues 23 (Lolagi Visinia, George Moala tries; Ihaia West 3 pens, 2 cons)
Bulls 18 (Jan Serfontein 2 tries; Handre Pollard 2 pens, con)
Halftime: 16-13