The Blues hammered the Waratahs 31-17 in Auckland after a first half blitz that saw the Blues score five tries.
The Blues scored their fourth and bonus point try after 26 minutes and before the Waratahs had got themselves on the scoreboard.
The Waratahs trailed 31-7 at half time but managed to keep the Blues scoreless in the second half while adding 10 points to their own score.
The Waratahs scored three tries in all and launched several attacks at the Blues line in the final quarter but were not able to score the bonus point try.
Luke McAlister had a hand in three tries and kicked three conversions before being subbed in the third quarter.
McAlister usually plays at inside center for the Blues but has emerged as the leading candidate to act as understudy for Daniel Carter at flyhalf in New Zealand's World Cup squad after a broken jaw on Friday likely ruled out Highlanders contender Colin Slade.
The Waratahs had conceded only seven tries in seven matches before Saturday's game, and had not been beaten by the Blues since 2007.
The Waratahs handling errors and misjudged kicks fed the Blues counter attacks in the first half.
McAlister initiated, sustained and controlled the direction of Blues' attacks while testing the defense with deft kicks.
He combined well with fullback Isaia Toeava and winger Rene Ranger, who repeatedly cracked the Waratahs' defense out wide.
Props John Afoa and Tevita Meilau scored the first two tries for the Blues, although both touchdowns were created by brilliant back play in which McAlister was prominent.
He put through the kick from which Afoa scored and handled several times in the move which was finished by Mailau.
He also had a controlling hand in a 19th minute try to center Jared Payne. When Ranger touched down in the 28th minute, the Blues had already banked a four-try bonus point and led 26-0.
The Waratahs scored a try through center Daniel Halangahu but scrumhalf Alby Mathewson went over to give the Blues a 31-7 lead at the interval.
The Waratahs gained far more possession in the second half and used it more effectively to slow the pace of the match.
Winger Mitchell scored their second try after 55 minutes and had a major hand in a 69th-minute try to Cross.
Fullback Kurtley Beale managed only one goal from four attempts.
Final Score Blues 31 Waratahs 17
Tries - J Afoa,T. Mailau,J Payne, R Ranger, A Mathewson
Con - L McAlister 3
Tries - D Halangahu, D Mitchell, R Cross
Con - K Beale
Referee: Mark Lawrence (South Africa)
Assistant referees: Craig Joubert (South Africa), Jonathon White (New Zealand)
Television match official: Chris Pollock (New Zealand)
Blues: Isaia Toeava, Joe Rokocoko, Jared Payne, Luke McAllister, Rene Ranger, Stephen Brett, Albie Mathewson, Peter Saili, Luke Braid, Jerome Kaino, Anthony Boric, Kurtis Haiu, John Afoa, Keven Mealamu (capt), Tevita Mailau.
Reserves: Tom McCartney, Pauliasi Manu, Filo Paulo, Chris Lowrey, Chris Smylie, Lachie Munro, Benson Stanley
Waratahs:15. Lachie Turner , 14. Tom Kingston , 13. Ryan Cross , 12. Daniel Halangahu , 11. Drew Mitchell , 10. Kurtley Beale , 9. Luke Burgess , 8. Ben Mowen , 7. Pat McCutcheon , 6. Dave Dennis , 5. Kane Douglas , 4. Dean Mumm [c] , 3. Sekope Kepu , 2. Tatafu Polota-Nau , 1. Benn Robinson,
Reserves 16. John Ulugia , 17. Al Baxter , 18. Pat O'Connor , 19. Sitaleki Timani , 20. Chris Alcock , 21. Brendan McKibbin , 22. Sosene Anesi , (23rd Man - Josh Holmes )