Having edged out the Dragons 24-20 10 days previous, the visitors found life particularly tough against a Gogledd side that has already beaten Blues North this season. In the end they were deserved, albeit narrow, 19-14 winners.
Roddy Smith scored the South’s lone try – in the first half – with Thompson adding a conversion and penalty to hand the visitors a 10-0 interval advantage.
Tries from Aaron Gwyn and Lewis Baker kept the North in the game after the break, but three further penalties from Thompson, who now has 59 points for the season, made sure.
Joe Simpson converted the two Gogledd tries but it was not enough to bring the hosts any joy in a game that also saw four yellow cards.
Blues South manager John Richards said; “It was a long journey and I think we started to feel that in the second half.
“Thankfully we stayed in front and came home with a very decent victory. All credit to the North, they came at us strongly in the second half and scored two good tries.”