Wales captain Sam Warburton hailed the impact of the home crowd in Cardiff after a phenomenal 23-16 win over Ireland.
Wales had to win to have any hope of lifting the Six Nations title this year following their opening loss to England.
Producing an unbelievable defensive effort, a total of 269 tackles, Wales fully deserved their victory.
"I'll tell you what, that's one of the most tired and exhausted I've felt after a Test match for a long time, it was an absolutely unbelievable effort," said Warburton.
"There was so much emotion building up to all week to this match, we knew we can't have a second chance anymore, we have to win every game we have and it was just an unbelievable effort from the boys.
"And as always, the Millennium Stadium is an unbelievable crowd, so definitely the 16th man."
"Ireland, to their credit, they just kept coming and coming all the time, went through a lot of phases, and in defence it was so tough.
"We just said all we have to do is keep our discipline, no penalties, we struggled with that in the second half over the first half.
"But the main message coming back out was to win the penalty count and hopefully that would see us over the finishing line."
Warburton added that Wales never lost confidence that they might win the Six Nations title this year despite that opening defeat.
"We were confident even after we lost the first game, the majority of Championships these days are not won by Grand Slams so we just had our title hopes up after the first game but there's still a lot of work to do," he added.
"By no means do we expect to go out to Italy and win so we're going to have another massive week of preparation and then it's still out of our hands with points difference to take into account but all we can do is try and go out to Italy and get a win a hope for the best."