Both teams gave it their all in pursuit of two precious Championship points, with Scott Williams' 62nd-minute try and Leigh Halfpenny's accurate goal-kicking proving crucial in getting Wales over the finish line.
Ireland recovered from a sloppy start where the Welsh were able to take a 12-0 lead thanks to Halfpenny's boot, but individual errors from the visitors and an almost watertight Welsh defence made for an ultimately frustrating day for Joe Schmidt's men.
Although three Jonathan Sexton penalties were added to by a penalty try, awarded for a collapsed maul in the 69th minute, Halfpenny decisively knocked over his fifth successful penalty with five minutes left.
The Welsh produced a huge display in defence, making a mammoth 289 tackles as they continually thwarted Ireland just metres from the try line. Captain and man-of-the-match Sam Warburton certainly delivered the goods for his side along with lock Luke Charteris who put in an incredible 37 tackles.
Ireland were unable to mark Paul O'Connell's 100th cap with a win as they tasted defeat for the first time since losing to England in February of last year. However, they will head to Scotland next week still in the hunt for a second successive RBS 6 Nations title.