Tom Prydie, Bowdy Davies (2), Adam Collins and Ryan Jones (2) crossed for tries with fullback Prydie adding four conversions. Having lost only once this season, the Ospreys were always in control of a game which saw them lead 19-6 at the interval.

A second half try for Scott Curtis and two penalties and a conversions for Diggy Bird provided some consolation for a Blues South side who now need to win their remaining games to reach the final.

In the other game, the Dragons went down 25-12 to the Scarlets at the Recreation Ground, Tredegar. Luke Williams, Luke Hamilton and Gareth Evans crossed for tries as the visitors kept alive their slim hopes of reaching the final.

Grant Rogers and Lewis Roblin bagged tries for the Dragons, who trailed 22-0 at half time, but it was not enough to provide the hosts with a much needed victory.

Blues South: E Jones; I Mortimer, N Gumbleton, A Cooke, D Evans; D Bird, S Curtis; M Savery, J Deabrau, L Davies, R Tucker, T Connolly, J Wilson, R Fenton, D Crimmins

Replacements: J Tomlinson, J Gape, K Hopkins, M Buckler, J Lewis, D Lakin, T Luck
(Travelling Reserves: K Paylor, F White)

Ospreys: T Prydie; B Davies, S Hughes, A Collins, E Walker; O Williams, R Jones (Capt); C Curtis, S Pick, D Saines, B Davies, S Treharne, R Apsee, M Sully, D Baker

Replacements: T Habberfield, M Morgan, B Barlow, R Thomas, L Evans, L Joseph, J Martin Fraser

Dragons: S Bevan; L Foley, M Jolly, A Herbert, A Cooper; D Carter, R Paul; L Ford, L Jones, A Yule, R Griffiths, R Wilson (Capt), G Hobbs, C Penna, G Evans

Replacements: J Evans, L Robling, L Smalley, G Ridgers, J Richardson, L Bacon

Scarlets: I Griffiths; T Ellis-Williams, D Ford, L Williams, J Russell; D Dafydd, A Davies; B Toms, G Isaac, S Lee, L Reynolds, L Hamilton (Capt), S Parry, M Dininno, K Myhill

Replacements: J Kaijacks, O Lloyd, R Evans, G O'Reilly, T Wiliams, S Charlton, R James, K Isaac