Wales captain Lee Briers showed his experience as his late drop-goal was the difference as Iestyn Harris' team beat Ireland in the European Cup.
Mark Lennon and Rhys Williams scored twice as Wales set-up a winner-takes-all showdown in France next week for qualification to the 2011 Four Nations.
Huddersfield star Gregg McNally scored 18 points for Ireland - including a late try - but Wales held on in Neath.
Ian Webster and Christiaan Roets also touched down for Wales at The Gnoll.
The Welsh, who thrashed Scotland last week, won by the narrowest of margins against Ireland and will travel to Albi knowing victory against France would secure qualification to rugby league's 2011 Four Nations showpiece alongside England, Australia and New Zealand.
