In the first half dominated by the large Blues South pack the team established an early 14 point lead.
Tries by Josh Pritchard and winger Tom Slocombe, both converted by Glen Evans, in the first quarter looked to have been the first of many that the Blues would score.
That this was not to be was a tribute to a gallant, determined and at times skilful performance by Swansea. In the first half Jack Thorburn of Swansea scored a try to reduce the Blues lead.
After the break Swansea took the attack to Blues South. A well organised defence and some ill discipline meant that Swansea did not add to their points tally until the last five minutes when Kier Nayland-Davies scored a try converted by Matthew Kenny.
The last few minutes of the match were tense for Blues South as they clung on to their narrow lead.
While the Blues South A deserved the victory the Swansea players can take credit for giving their opponents a great battle.