"You can't concede four goals at home and expect to get anything from the game - that's the bottom line," Holland told the Nottingham Evening Post in the Bank Holiday Monday edition.
"The defensive shape of the team was not good and the players know that they have let themselves down.
"We know we have to do better than that as a squad. We need to defend as a team and we didn't do it.
"But it is up to us now to work hard and rectify the problems to make sure this type of thing doesn't happen again."
"You have not really got much of a chance when you are 3-0 down at half-time. We know we have goals in the side and we have proved that already, but we have to start keeping some clean sheets.
"It was disappointing that Richie didn't score the first penalty because things might have been different but you can't knock his record since he has been here.
"Despite the scoreline at half-time, we still went out for the second half with the belief we could get something, but then we shot ourselves in the foot by conceding another penalty, which they scored, and then we had an even bigger hill to climb."