The Blues have extended their winning streak against the Waratahs and secured the first Super Rugby Pacific semifinal spot.
Forced to come from behind, the Blues won 41-12 for a ninth consecutive victory over the team from New South Wales.
The visitors struck early at Eden Park on Friday night with Waratahs forward Ned Hanigan crossing for the opening try in the third minute.
A penalty followed by a try to halfback Finlay Christie who was on the end of a breakaway gave the Blues the lead before the 20 minute mark.
Both teams had tries disallowed for grounding before Blues' Nepo Laulala drove over for his first try in a couple of years to extend the lead to 17-7 at halftime.
The home side were dominant after the break having found their rhythm with tries to Ricky Riccitelli and Zarn Sullivan in the space of eight minutes to add to the Blues' advantage.
Winger Mark Telea equaled the Blues' season record of 12 tries when he ran in the team's fifth of the night.
The Waratahs scored a consolation try in the 70th minute to Dylan Pietsch.
No Australian side has won a play-off game in New Zealand in 27 years of Super Rugby while the Waratahs have now lost their last eight at Eden Park, dating back to 2009.