After seven dynamic caps off the bench, 21-year-old back rower Henry Pollock finally gained a first Test start.
The idea was his energy would help avoid a repeat of last week when Scotland blitzed England in the opening 20 minutes.
“What do you do? Two weeks in a row conceding so many points in the first 15 minutes,” prop forward Ellis Genge told BBC Sport.
“Everyone has to take a look at themselves. No-one knows what the answer is right now or we would have sorted it out.
“It opened up scar tissue from last week – we have to be better at managing that period and stop turning the ball over.
“It’s brutal, professional sport because if you get 5% wrong it’s gone. We probably believed the hype from the first week too much. We can’t let the noise in now.
“We have let everyone down. Apologies for that but I promise we will make it better. We are going to go away and work as hard as we can to go away and rectify things.”
England found themselves deep in Ireland’s 22 on multiple occasions but lacked any clinical edge, making 14 handling errors in the game.
George Ford also missed touch with a penalty that could have put the hosts in a scoring position.
“As players, senior players and the leadership team we have to take responsibility for not starting the game right,” said Itoje.
“It was just our inaccuracy. We turned the ball over too much, and when we did get into positions to hurt Ireland we were not accurate and then gave ourselves a mountain to climb.”