Blues North under 16s brought to an end the Ospreys' unbeaten run in the WRU Age Grade Championship and at the same time registered their first victory of the season.
After kicking off the campaign with defeats against the Dragons, Scarlets and Gogledd Cymru, the North edged out the Ospreys 19-17 in a real thriller at Pontypridd's Sardis Road.
Centre Callum Phillips, Joel Riggs and Josh Flye bagged tries for the hosts with Phillips and James Dixon adding a conversion apiece.
For the Ospreys, there were tries from Ryan Evans and Nicky Smith whilst Dan Thomas and Sam Davies added conversions and Thomas a penalty.
Team manager Nigel Way said; "we haven't been far away in our other games, but credit to the boys for sticking with it and coming away with a first win of the season."
Having started the season so brightly, defeat means the Ospreys slip further behind runaway leaders the Scarlets who defeated the Dragons 36-16 at the Recreation Ground, Tredegar.
With three victories under their belts already, the Scarlets bagged another bonus point in beating the Gwent region by four tries to two.
Jake Randall and Thomas Ball crossed for tries in the first half as the visitors swept into a 21-8 interval lead.
After that, it was a straightforward evening for the Scarlets as Sion Bennett and Dylan Morgan crossed for tries number three and four.
Jordan Williams, who went into the game with 55 points, kicked four penalties and two conversions as the Scarlets eased to another consummate victory.
Michael Adams and Dominic Franchi scored tries for the Dragons with Ethan Davies adding two penalties.
Warren Gatland has confirmed he will be joining the fast approaching 50,000-strong crowd at Judgement Day III on Saturday to run the rule over potential Wales Rugby World Cup squad members in the competitive surrounds of the Millennium Stadium.
Cardiff Blues are hosting a special Open Evening this Wednesday night at BT Sport Cardiff Arms Park to give prospective students and parents the chance to discover more about our new and exciting rugby education programme.
Our Cardiff Blues Rugby Camps return this Easter to give children right across our region the opportunity to participate in rugby during the holidays - and after selling out our last two camps you can book NOW to avoid any disappointment!
The players at Cardiff Blues will be hoping to play with some true Gallic flair for the rest of the Guinness PRO12 season - after the region teamed up with a successful French bistrot in the Welsh capital.
Cardiff Blues will be celebrating St David's Day when the region faces Edinburgh Rugby at BT Sport Cardiff Arms Park on Sunday afternoon (kick-off 12.45pm) - with hundreds of children invited as part of our Regional Schools Day.
Fine footwear retailer The Brogue Trader - one of the official sponsors of Cardiff Blues - is celebrating after being recognised by the British Footwear Association at its annual Footwear Industry Awards.
Battling Cardiff Blues produced a second half performance packed full of character and spirit to push Ulster Rugby all the way in an absorbing Guinness PRO12 encounter at a packed out Kingspan Stadium.