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.
Existing Season Ticket holders are advised that full details of all packages for the 2015/16 season have now been posted out to you and will arrive in the coming days - and that the deadline to renew your seat has now been extended!
Supporters are advised that Cardiff Blues will be holding a presentation on the field post match on Saturday afternoon to mark those players leaving the region, hand out caps and the end of season awards.
Cardiff Blues face Zebre in the last Guinness PRO12 game of the season at BT Sport Cardiff Arms Park this Saturday, (kick-off 3pm) - and the ladies of the region can meet players such as Cory Allen and Ellis Jenkins while enjoying a special day with the Blues!
First team stars Cory Allen, Ellis Jenkins, Adam Jones and Kristian Dacey were among the special guests as Cardiff Blues held the Sphere Solutions Blues Tag Rugby Festival at BT Sport Cardiff Arms Park.
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.