In the other match, the Ospreys entertain the Blues at St Helens after the game was swicthed from the Old Parish, Maesteg due to the condition of the pitch. The Blues were disappointing first time out - going down to a young Dragons side at Abertillery - and they threw away the chance of redeeming themselves three weeks ago when the Scarlets travelled to Llanharan and secured a 30-26 success.
The visitors have to win to stand any chance of reaching the final whereas a victory for the Ospreys, who have won one of their two games so far, will edge them a step closer.
U20 Week 3 Fixtures
Ospreys v Blues, at St Helens, Kick Off 7.15pm
Scarlets v Dragons at Narbeth, Kick Off 7.15pm