Robbie Henshaw has admitted that he made a critical error at a crucial stage of Friday night's loss to Wales by joining a forward-marching maul in front of ball-carrier Rory Best.
With the game in the balance, Ireland mauled the ball to within inches of the Wales line and the centre rushed in from midfield to try and propel his captain over the line.
In his enthusiasm, Henshaw sprinted past the ball and came into the maul from an offside position and when Best touched the ball down his try was ruled out correctly by referee Wayne Barnes.
After the game, Joe Schmidt repeatedly pointed to the incident as a pivotal moment and the Leinster star, who otherwise had an excellent game, held his hands up.
"My entry wasn't the best, instead of coming in from the side I should have come from behind and I got that wrong," he said.
"It was just me not knowing the rules and obviously we suffered as a result.
"I thought it was turning, so I thought he (Rory Best) was going to break out and I was potentially going to latch on to him and help him drive over.
"So, it was just one of those calls where I came in quite fast as well so I didn't really have time to readjust.
"I've put my hand up anyway, it was a mistake.
"(I should have) come square, more at Besty's backside area rather than his side. You have to come from behind.
"It's technical stuff, I'm not a forward. I thought it was going to slow down and if we stick one more body in and we'd get over. I've seen them given before."