The Blues put one over on the Ospreys in last night's penultimate pool game in the WRU Regional under 18 Championship at Jenner Park in Barry.
However, their 25-22 success in front of a record attendance for the competition - 1300 - does not affect the overall standings in the table.
In fact with the two sides having performed so well in the opening three months of the season, they will meet once again at the end of next month in the final at Llandovery.
With that game in mind, the Blues were understandably keen to strike a physcological blow. And they achieved that courtesy of tries from captain Jake Thomas, Christian Dacey and Lloyd Williams and three conversions and a long range penalty from Joe Deacon.
They led 15-12 at the interval with high performance manager Gafyn Cooper delighted with another excellent performance.
He said, "It was another great night for the boys. The staging of the game could not have been better and the crowd was far and away the biggest we have played in front us.
"They are a good side and made life really difficult for us, but we held on and Joe Deacon's penalty from half way earned us an excellent win."
In the other game, the Dragons recorded a 34-10 win over the Scarlets at Abertillery Park.
Thank Blues it's Friday! The weekend will be starting HERE on Friday night as Cardiff Blues tackle Ulster in the Guinness PRO12 at BT Sport Cardiff Arms Park - and we want you to be our guest at our big match day party!
Let the Games Begin! Cardiff Blues launch the Guinness PRO12 season on home soil this Sunday afternoon against Glasgow Warriors (kick-off 4pm) - and we are going to make it a double celebration as we also recognise the achievements of Team Wales!
First team aces Cory Allen, Lloyd Williams, Ellis Jenkins and new signing Jarrad Hoeata were all on hand to watch the next generation of stars when Cardiff Blues held a huge Under-8s Tag Rugby tournament at BT Sport Cardiff Arms Park.
Clinical Glasgow Warriors produced a devastating final 20 minutes to secure the points on Super Sunday and consign battling Cardiff Blues to a 33-12 defeat in the Guinness PRO12 opener at BT Sport Cardiff Arms Park.
Impressive Cardiff Blues pushed English powerhouse side Leicester Tigers all the way with an hugely encouraging performance as final preparations for the new Guinness PRO12 season continued at Welford Road.