He said: “We played with nine men in the first game against Celtic, 10 in the final last week and Wednesday night took its toll physically.
“But this game was more of a mental thing, especially in the first-half. I thought we lacked belief.
“I could see a few of us feeling sorry for ourselves.
“I thought we were quite soft a number of times in the first-half, but the second was better.”
On Gary Mackay-Steven’s 25-yard drive which set the home side on their way to victory, McNamara said: “It was a good strike, but we should have been out a bit quicker.
“It came a through a few bodies and I don’t think our keeper Radoslaw Cierzniak had any chance.
“Gary has that quality, we all know that but I was disappointed with the other two goals we lost.”