A winning try by Ireland’s Gillian Bourke coupled with the home side’s failure to take full advantage of their second-half dominance proved decisive in a tight encounter.
Guest said: “It was a dogfight, and we always knew it was going to be. It was a huge team effort and our defence was so brutal. We were nice and patient in the second half and thankfully it paid off.”
Ireland went ahead after a try by second-row Sophie Spence — who would be sin-binned minutes later — was converted by full-back Niamh Briggs.
Wales capitalised on their numerical advantage as full-back Rosie Fletcher went over late in the first half and Elinor Snowsill duly converted to make it 7-7 at the break.
The hosts began the second half the better but a sturdy defensive effort and a missed penalty by Wales’ Snowsill kept Ireland in the game.
Their superiority resulted in another sin-bin for the visitors, this time for replacement hooker Stacey-Lea Kennedy who had only been on the field for a few minutes.
Laura Prosser kicked over the resulting penalty to give Wales a lead for the first time in the match.
But with only minutes remaining, some great offloading by Ireland led to what turned out to be the winning try by Gillian Bourke, who had been thrown back on after the sin-bin.
Next week sees Ireland welcoming tournament favourites England, and Guest is looking forward to the clash. “I can’t wait,” she said. “It will be very hard but we are not afraid of anybody.”
Scorers for Wales: R Fletcher. Cons: E Snowsill. Pens: L Prosser.
Scorers for Ireland: S Spence, G Bourke. Cons: N Briggs.
WALES: R Fletcher; C James, E Evans, R de Filippo, P Tuttiet; E Snowsill; A Day; M York, L Harries, C Edwards, G Hallett, S Powell Hughes, C Nicholas, S Harries, R Taylor (C).
Replacements: C Phillips, B Howell, J Davies, N Davies, V Owens, L Prosser, D Hywel, R Taylor.
IRELAND: N Briggs; N Kavanagh, G Davitt, J Murphy, A Miller; L Cantwell; L Muldoon; F Coghlan (Capt), G Bourke, A Egan, S Spence, M Louise Reilly, L Guest, C Molloy, J Neville.
Replacements: S-Lea Kennedy, F Hayes, L Day, H O’Brien, S Fleming, A Davis, N Stapleton, A Baxter.