Wrexham started on the front foot against Watford and led through Josh Windass’ sixth goal of the season.
But the visitors looked on course for just a second away league win of the season as goals from Mamadou Doumbia and Othmane Maamma before half time put Javi Gracia’s men 2-1 up.
Rathbone provided the pivotal moment in the second minute of added time though as Wrexham extended their unbeaten league run at home to eight matches.
“It was important we did that today and I felt we deserved it,” Parkinson said of his side’s impressive home form.
“When you’re chasing the game like we were, I felt we did it in a controlled way and I was relatively pleased with that.
“Some of the crosses needed to be better and of course the final bit of composure, but I felt we worked our way back into the game in a very controlled way.”
