Cardiff Blues are almost certain to miss out on a place in the WRU Regional under 20 Championship final after suffering a 35-8 defeat at the hands of the Ospreys at St Helens.
There were five tries in all for the Ospreys with James Pike helping himself to a couple in a one-sided affair.
The Blues have struggled this season to gather any momentum despite being tipped at the beginning of the season as one of the probable front-runners.
Gareth Williams-Davies kicked a penalty for them in the first half and Jamie Roberts added a second half try.
However, the Ospreys, after being held early on, were head and shoulders above their visitors with Pike, Lee Bevan and Sam Kiley crossing for first half tries.
Jason Howells and Pike with a second scored in the second half with Jonathan Spratt adding a couple of conversions and as many penalties.
Meanwhile the Dragons suffered a second defeat of the season, against the Scarlets at Narberth.
By Graham Clutton