The Souters are almost – but not quite – assured of a coveted top six spot, with the two teams below them, Gala and Musselburgh, each having two games left to play.
The top half-dozen are set to make the trip upstairs next season to join the four teams not involved in the new Super 6 venture.
Selkirk welcome Gala to Philiphaugh after getting back on the winning trail at Musselburgh last weekend.
Following a couple of disappointing slender losses, the Souters scored a bonus-point 15-34 victory at Stoneyhill.
“Musselburgh were a stuffy side – they played rugby right to the end,” said Souters manager Tom Ramage.
“Even though we scored a fourth try through (Darren) Clapperton, they never gave up.”
Ramage added: “It was ‘winner takes all’ game, to be honest, like being in a relegation battle. No one wants that seventh spot.
“Our forwards played really well. We played the game at our pace, whereas before, it used to be quite erratic.
“But we just built our phases, took our time and let the breaks happen, rather than trying to force everything.”
Selkirk worked out the details of the rucks, mauls and scrums and put a lot of hard work in.
“There was good communication and it reaped dividends in the end,” said Ramage.
Gala, who were defeated narrowly at home 22-26 to GHA at the weekend, play leaders Marr in their final game, while the Maroons went down 17-26 to Selkirk when the sides last met at Netherdale in November.
Ramage said Selkirk had no injury worries for tomorrow and they hoped to secure a win by breaking down Gala’s game and finding the cracks in their armour.
“The ‘try fest’ had faded a wee bit but patience is a virtue now and the tries are beginning to come back,” he said.