"We dominated for long periods in the first half and yet ended up 3-0 down at half-time," he said after the game which left Watford without a home win since 20th October.
"I was pleased with our attacking play but not some of the defending. It was schoolboy stuff.
"There was no ranting or raving at half-time, we just talked about what we had to do to. We got back into it and then left ourselves open."