Shane Long's brace gave Reading a fine win at Pride Park and McDermott dedicated the points to those who made the treacherous journey.
He said: "When I came out before the game I was amazed that we had any fans at all.
"I know how bad the conditions were at home so congratulations to those who made it. A great effort.
"The whole afternoon was a credit to the club and I'm just glad we gave them a victory."