The Blues battled hard in the face of some late pressure to overcome the Bulls 23-18 at Eden Park as the struggling New Zealanders registered just their third victory of the Super Rugby season.
The Bulls did earn a losing bonus point to leapfrog the Stormers at the top of the South African conference standings but will rue a missed chance to claim victory when they gave up a late try.
Both teams scored two tries but the Blues got the decisive touchdown 12 minutes from time when inside centre George Moala crashed over.
Blues first five Ihaia West landed his second conversion after booting three first half penalties in what proved the difference with the Blues defence holding out the Bulls in the final few minutes.
Standin captain Keven Mealamu said the boys really stuck to it tonight - it was never going to be easy but they did a good job and this would build some confidence for next season.
Blues captain Steven Luatua did leave the field with what appeared to be a serious shoulder injury.
The Blues scored the opening try in the 18th minute when Bulls flyhalf Handre Pollard failed to find touch with his clearance kick and home fullback Lolagi Visinia scored on the counter-attack.
The South Africans did close the gap before halftime when Jan Serfontein scored near the posts then grabbed the lead after the break when the centre scored his second try.
However, the Blues regained the lead when Moala dived over from close range after a long build-up of pressure then kept the visitors scoreless for the rest of the match.
The Blues are still last in the New Zealand Conference.
Meanwhile, the Queensland Reds piled on 40 unanswered points in a 33-minute blitz to come from behind and thrash the Melbourne Rebels 46-29 in an all-Australian Super rugby clash in Melbourne.