Merthyr Town 5-3 Swindon Supermarine
Merthyr Town are one win away from securing promotion to the Southern League Premier Division.
The Martyrs beat Swindon Supermarine 5-3 in the Division One South & West semi-final at Penydarren Park.
They will be at home in Monday's final against Paulton Rovers, who beat Tiverton Town 3-1 in the other semi-final.
The Welsh side finished the regular season as runners-up to Cirencester Town in Division One South & West.