Both sides kept the ball alive in stunning playing conditions but Wales were well worth their victory. The forwards toughed it out where back row Catrina Nicholas was outstanding in defence, supporting inspirational skipper Berry while Clare Flowers always posed a threat in midfield for the home side with her powerful running.
Wales entered the game having made one change to the starting line-up which brushed aside Italy six days earlier, with prop Jenny Davies replacing Claire Horgan who dropped to the bench.
The Waterloo front rower repaid the faith shown in her by powering over in the second minute after Flowers carved open the Irish defence to get Wales off to the perfect start.
Non Evans had an opportunity to extend the lead but her penalty sailed wide but she made immediate amends when latching onto a brilliant Nicholas flick pass to slash her way over. Evans's conversion hit the uprights so Wales had a 10-0 buffer after 10 minutes.
Clearly stunned by the early onslaught, the Irish finally got a foothold in Welsh territory to set up a penalty opportunity which full back Niamh Briggs accepted to register the visitor's first points.
Briggs had a chance to reduce the arrears with a shot at goal from exactly the same position on 21 minutes but she fluffed her attempt to keep the score at 10-3.
The roles were reversed as Ireland went on the attack and it was Wales's turn to defend. Wing Lynne Cantwell had already shown glimpses of her speed but it was her guile from a set move which sent Wales's defence into panic mode. She burst through the middle of the park and only a last gasp tackle prevented the speedster from scoring.
After defending for a lengthy period, Wales finished the half with a flourish. Quick ball from a lineout 15 metres out saw the backs fling the ball wide and Evans sped to the corner but was bundled into touch inches from the try-line by her opposite number Cantwell. As the teams went into the break, the game was still delicately poised with Wales leading 10-3.
Eight minutes into the second half Shannon Houston produced a solo effort to shake off two tackles to race to the posts unopposed to give Briggs an easy conversion to level the score at 10-10.
Ireland were then reduced to 14 players when hooker Yvonne Nolan was sent to the sin bin for lying on the ball. Wales struggled to make their superior numbers count but eventually Evans popped over a penalty to put the home side back in front 13-10.
Ireland continued to give the ball plenty of width with Briggs and replacement winger Amy Davis posing threats but with Berry leading from the front, Wales snuffed out the danger with bone jarring tackles.
Wales were living dangerously and nearly saw their hopes dashed when Irish centre Helen Brosnan dropped the ball when going for an intercept. With time running out Briggs had a long range shot at goal but her shot went wide.
As the seconds ticked by, Welsh fans were becoming increasingly concerned but Wales held out for another momentous victory in what has been a rousing season for the Wales Women.
Wales: Tries - Jenny Davies, Non Evans; Pen - Non Evans
Ireland Try - Shannon Houston; Con - Briggs; Pen - Briggs