The Ospreys advanced their claims to be the best side in Wales with a five-try demolition of the Blues.
Ospreys: (13) 39: Tries: D Jones, Bishop, Spice, Henson, Parker. Cons: Henson 4. Pens: Henson 2.
Blues: (3) 3: Pen: L Thomas.
A Duncan Jones try, plus two penalties and a conversion from Gavin Henson gave the Ospreys a 13-3 half-time lead.
But a second-half blitz saw David Bishop, Jason Spice, Henson and a 40 metre effort from Sonny Parker earn the Ospreys a satisfying victory.
The Blues had just a solitary Lee Thomas penalty to show at the Gnoll against their rampant hosts.
Henson drew first blood for the Ospreys with a 10th-minute penalty, but the home side did not take long to turn their early dominance into more points.
Adrian Durston's break up the left-hand side sucked in the Blues defenders and Spice was quick to spot the space on the other flank.
The scrum-half flipped an overhead pass to Ryan Jones, who unselfishly fed the ball on to prop Duncan Jones for a converted try.
Lee Thomas got the Blues on the scoreboard after 26 minutes with his first successful penalty, having missed two more testing kicks earlier.
Play was held up for several minutes after Blues full-back Rhys Williams was pole-axed trying to tackle the rampaging Parker.
The visitors were forced to bring on Dean Dewdney for Williams, then had to endure another Henson penalty as the Ospreys fly-half gave his side a 13-3 half-time lead.
Soon after the restart, with referee Donal Courtney playing advantage, Shane Williams tried a speculative drop-goal that drifted wide.
But Blues replacement Nick Macleod allowed the ball to bounce behind the try line and Bishop needed no second invitation to pounce and score, Henson converting.
A series of drives took the home side deep into the Blues 22 and Spice sold Gethin Jenkins an outrageous dummy from the base of a ruck to score the Ospreys' third try, Henson again converting to make it 27-3.
Henson had bossed the game from fly-half and gave watching Wales coach Mike Ruddock another nudge with a try in the 66th minute.
The 22-year-old brushed through some weak Blues defence, handing off Martyn Williams in the process to score the Ospreys' fourth try and claim a precious bonus point.
Henson missed the conversion, his first black mark of the night, but was handed another go from the kick-off as Bishop claimed the restart and sent Parker 40 metres to score under the posts.
Ospreys: A Durston, D Tiueti, D Bishop, S Parker, S Williams; G Henson, J Spice; D Jones, B Williams (capt), A Jones, A Newman, L Bateman, J Thomas, R Pugh, R Jones.
Replacements: A Williams, Hook, Brew, A Millward, M Davies, James, Lloyd.
Blues: R Williams; J Vaughton, T Shanklin, T Davies, C Morgan; L Thomas, R Smith; G Jenkins, G Williams, M Jones, D Jones, R Sidoli, M Lewis, M Williams (capt), K Schubert.
Replacements: K Fourie, A Lewis, B Evans, H Senekal, N Thomas, D Dewdney, N Macleod.
Referee: Donal Courtney (Ireland).