McDermott was frustrated they could not see out the game but felt his side should have had a penalty for a foul by Maynor Figueroa on Jay Tabb when the score was 1-1.
"I thought we deserved a point, and I thought it was the least we were going to get," said McDermott.
"I think if the referee had given the penalty on Jay Tabb we would have gone on to win the game. Someone of Howard Webb's experience and quality, you would have expected him to get that one right.
"When you're 2-2 in the 92nd minute and we've got the ball, you've got to make sure you see the game out. If you have to take a point in this league then take it and move on.
"We have to learn quickly from that. We've seen out the last couple of games really well but unfortunately we haven't seen this one out."