Speaking after the 3-2 defeat to BBC Coventry & Warwickshire, Boothroyd said: "The fans were brilliant, outsinging the home support.
"We though they would have a hangover and they were when we went 2-0 up.
"We had to make sure we manage the game but they scored a great goal and I knew we would have to deal with a storm. But rather than hold them, we gave them momentum.
"We wanted to go toe to toe with them but what sometimes happens when you do that is that you get knocked out.
"I want us to have an understanding of winning matches but what we have done is played the occasion rather than the game and we have shot ourselves in the foot.
"King and Gunnarsson challenged well as did all our players in the first half but it was schoolboy stuff in the second.
"I'm frustrated and irritated as this was a good opportunity to go through."