Matt Silva’s side saw off regional rivals and previously unbeaten Blues North in a local derby at Abercynon last week and will be hoping for a similar result tomorrow.
“It was a deserved win for the South and a little against the run of form given that the North were previously unbeaten,” said Blues Performance Director Richard Hodges.
“They dominated from start to finish and answered a couple of questions we might have had about them following their defeat to the Ospreys.
“They were excellent from beginning to end.”
Following their win last week, the South will be full of confidence but face a difficult trip to Ebbw Vale to take on the Dragons.
The home side may not have had the best of starts to their age grade campaign but boast some dangerous backs in the form of Arwel Robson and wing James Scarfi.
Lock Bryce Morgan and the rest of his pack will also provide a stern physical test for the Blues, one they will have to match if they are to follow up last week’s win with another victory.
In the other game taking place tomorrow, the Scarlets welcome the Ospreys to Parc y Scarlets in what is sure to be a competitive fixture.
Shaun Edwards captains the home side from flanker while Billy McBryde will be looking to get his backs moving from outside-half.
Dragons: 15 Arwel Robson 14 James Scarfi 13 Patric Lewis 12 James Hussey 11 Lewis Phillips 10 Josh Malson 9 Dom Quigley, 1 Cory Greenaway 2 Jack Davies 3 Leon Brown 4 Bryce Morgan 5 Lewis Johnson 6 Lloyd Phillips 7 Dawid Rubasniak 8 Matthew Donovan.
Replacements: Jack Williams, Brandon Mustoe, Jack Kedward, Conner Jones-Graves, John Viney, Owian Leonard, Barney Nightingale, Roy Furnival.
Blues South: 15 Jesse Lipetz Robic 14 Josh Rodgers 13 Teri Gee 12 Nick Griffiths 11 James Walsh 10 Luke Fish 9 Myles Churcher, 1 Sam Brinkworth 2 Aldi Coverdale 3 Joel Ringer 4 Cengizhan Ziyaeddin 5 Tom Hayward 6 Sid Blackmore (c) 7 Cameron James 8 Joe Gaughan.
Replacements: Will Haines, Matt Holder, Rhys Forse, Dan Holder, Harry Dowell Bennett, Adam Dix, Alex Guard, Jon Hunt.
Scarlets: 15 Jack Evans 14 Gwion Jones 13 Kieran Jones 12 Matthew Pearce 11 Shaun Pearce 10 Billy McBryde 9 Rhodri Rees, 1 Rhys Fawcett 2 Zac Phillips 3 Richard Bassett 4 Josh Macleod 5 Stephen Leonard 6 Steffan Davies 7 Shaun Edwards (c) 8 Stefan Taffestauffer.
Replacements: Scott Jenkins, Matthe Moore, Jamie Hughes, Colin Markham, Shaun Evans, Joe Chiffi, Daniel Gealy, Harry Randall.
Ospreys: 15 Morgan Jones 14 James Taylor 13 Stuart Nicholas 12 Owen Watkin 11 Regan Grace 10 Dylan Francis 9 Jordan Condon, 1 Sam Matthews 2 Jac Briggs 3 James Tanner 4 Chris Long (c) 5 Jacob Blackmore 6 Connor R Davies 7 Ben Davies 8 Joshua Cole.
Replacements: Rhydian Jenkins, Rhys Howells, Nicky Davies, Lloyd Webb, Jack Davies, Matthew Aubrey, James Davies, Rhys Gealy.