Ireland's Brian O'Driscoll admitted his side had failed to fulfil their potential as they lost 22-10 to Wales in the World Cup quarter-final.
"It was a great opportunity for us after winning the group," said the Irish skipper.
"We needed to deliver a performance similar to those against Australia and Italy but we turned over too much ball.
"Wales took their scores very well and showed they are worthy semi-finalists and good luck to them."
O'Driscoll added: "We got outplayed in the second half, they scored two good tries, maybe there was some weak defence but we are very disappointed to be going home."
The result sent Wales into the last four of the global showpiece for the first time since 1987 while Ireland have never made the semi-finals.
"It was always going to be a 50-50 game," said Ireland coach Declan Kidney.
"Wales scored three tries so there are no arguments from us."