The hosts took the lead with eight minutes played as Josh Yorwerth arrived unmarked to meet an Ian Traylor corner kick and power a header past Mark Scott. The goal came just a couple minutes after Slough missed a clear chance, Lee Togwell hitting the post after Ashley Evans cleared off the line from Simon Dunn.
Merthyr went close to doubling their lead when Traylor stepped inside from the right side of the box and hit a left-footed effort which Scott turned away. Slough broke away almost immediately, but Elijah Adebayo fired over the bar.
Slough were struggling to get into positions to test opposing keeper Oliver Davies. Lewis Putman lifted an effort over, and the hosts missed another good chance when Jarrad Wright pulled the ball across for Traylor, who put his shot over the bar.
But Merthyr were rewarded with a second goal six minutes before the interval as Keyon Reffell fed Kayne McLaggon, who hit a powerful 20-yard effort over Scott and into the roof of the net.
A different Slough emerged from the half time break, and the Rebels worked their way into the contest.
The Rebels started to test Davies, with Dobson having a shot easily saved and Adebayo seeing an effort blocked.
Charlie Moone, a half time replacement for Warren Harris, pulled a goal back on 71 minutes as he headed in James Dobson’s deep cross from the left wing.
Five minutes later, Slough pulled level through yet another set piece goal from Dobson, whose reputation as a specialist grows with every game. Dobson was fouled by Yorwerth 20 yards out, and stepped up to whip the resulting free kick across the defensive wall and into the far corner of Davies’ goal.
Both sides pushed for a winning goal but Merthyr were hindered by the dismissal of captain Evans for retaliating after Dobson had fouled him. From the resulting free kick, Gethin Jones failed to make proper contact with the ball six yards out, and Scott gathered the ball comfortably as the match ended all square.
Merthyr Town Line up
Oliver Davies, Ben Watkins, Scott Barrow, Ashley Evans (c), Gethin Jones, Jarrad Wright, Elliot Richards (Corey Jenkins), Josh Yorwerth, Kayne McLaggon, Keyon Reffell (Gavin Williams), Ian Traylor. Subs not used: Scott Tancock, Glyn Garner, Curtis Hutson.