Scott Sinclair's first-half strike was enough to snatch the points for the Swans.
McDermott said: "For the first half an hour there was nothing in the game but then they got the goal which made a lot of difference to them. They had a lot of opportunities and Adam Federici had to make a good save.
"In the first half there was nothing in the game but once you get that first goal it makes such a difference. "I couldn't fault our players for effort today. They always keep going right to the death but we lacked something."
Source: PA
