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.
Cardiff Blues face Newport Gwent Dragons in a massive 'all-Welsh' European Rugby Challenge Cup quarter-final at Rodney Parade in April - and the region is now pleased to announce that tickets are on General Sale NOW!
Egg-cellent news! 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!
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.
A powerful second half surge from new table-toppers Munster Rugby saw the run in three tries and wrap up victory over Cardiff Blues as the Guinness PRO12 season resumed at the newly-developed Irish Independent Park.
A total of 87 points, 12 tries and one unforgettable afternoon with Miles Normandale scoring a sensational injury time try as Cardiff Blues capped a staggering comeback to stun Wasps and take control of their LV=Cup destiny.