The match, which was McDermott's first in charge, was Leeds's first win for seven games.
The former Reading boss admitted that the fans made a difference after going a goal behind.
"I was really pleased," McDermott told Sky Sports News. "It was a hard first half and we knew we shouldn't have gone a goal down.
"We needed to pass the ball and create things and I thought the players were really brave in the second half.
"I told them at half time that the crowd really wanted to get behind them. I've been at places where that hasn't been the case but when we got to 1-1 it made a real difference."
Leeds's win took them six points clear of the relegation zone with just four games left to play.