Johnson furious at England indiscipline
England manager Martin Johnson said his team's indiscipline cost them the chance to beat Ireland at Croke Park.
Johnson's side clawed themselves back to within a point but again played 20 minutes with 14 players after the sin-binning of Danny Care and Phil Vickery.
"I'm trying to keep my cool," Johnson told BBC Sport after the 14-13 loss.
"It's very annoying. I've just told the guys that it has cost us a Test match. All that work you put in to try to win a game is gone, wasted."
Scrum-half Care's yellow card in the 69th minute, for a shoulder charge on Marcus Horan, was particularly galling as, at that stage, Ireland only led 11-6.
Johnson erupts at Care sin-binning
But Ronan O'Gara's penalty pushed them two scores clear and the outside-half's kick proved crucial after Delon Armitage crossed over for a try with two minutes remaining.
It is not the first time in this Six Nations that England have had to play with a man disadvantage.
They were made to play 20 minutes of the defeat by Wales with 14 men and had two players sent to the sin-bin during the opening win over Italy.
"It's not one individual doing it all, it's a number of individuals at key moments," added Johnson.
"We work on discipline all the time. One of the fundamentals of the game is not to be penalised.
"Once you get behind on the penalty count, the referee and touch judges are on your back and things like the Danny Care sin-binning happen.
"We lost the game by a point and gave 18 penalties away. When the penalty count gets twice as high as it should be then you're going to lose.
"I think we were a bit nervous in the first 20 minutes and we didn't build much pressure in the first half."
Steve Borthwick revealed that Johnson was "clearly angry" in the dressing room after the match and the England captain said his team needed to quickly learn from their mistakes.
"He was clearly angry, as are all the players and the coaching staff," said the Saracens lock.
Indiscipline cost us - Borthwick
"We give far too many penalties away and it's difficult to win Test matches when you're giving away kicks at goals and being yellow carded.
"If there was an easy fix (to our indiscipline) then we would do it. Quite clearly we need to learn as it's undoubtedly costing us Test matches.
"We know we let ourselves down. I think the players are facing up to it."