Wales slumped to their first defeat of the Six Nations Under-21 championship following a 30-19 defeat at Galway.
The defending champions, who clinched the Grand Slam last year, were brought back down to earth following last week's emphatic win over Scotland.
But despite only one change to that side - with the return of World Cup hooker Huw Bennett - Wales never got going until the final 20 minutes.
Two tries from replacement scrum-half Richard Rees led the Welsh comeback but it was not enough to recover from a terrible first half that saw them trail 22-9 at the break.
Playing into a stiff wind, Wales got off to the worst possible start when promising Cardiff prop John Yapp was sin binned for punching after just four minutes.
While he was sat on the sideline Ireland crossed twice through No 8 Jamie Heaslip and then captain David Gannon as the home side made their extra man count.
Pontypridd's Lee Thomas and Gareth Steenson then exchanged penalties before Ireland went over for a third try inside the half-hour when centre John Hearty collected a poor pass on the bounce to leave the Welsh defence standing.
Another mistake in midfield allowed wing Tommy Bowe a free run along the touchline for Ireland fourth as a rout appeared on the cards.
Wales to their credit rallied with the two Rees tries on 67 and 77 minutes but the two missed conversions summed up a frustrating afternoon.
IRELAND U21s: A Finn; R Lane, J Hearty, G Telford, T Bowe; G Steenson, T O'Leary; J Wickham, D Fogarty, D Fitzpatrick (S Bennett, H-T), D Gannon (capt), S O'Connor (N McComb, 80), B O'Connor (C Geoghegan, 30-40, D O'Brien, H-T, R Shaw, 77), J Heaslip, O Hennessy.
Tries - J Heaslip, D Gannn, J Hearty, T Bowe. Cons - G Steenson (2). Pens - G Steenson (2).
WALES U21s: M Nuthall; I Evans (G Evans, 79), R Payne, L Thomas, F Brillante; S MacLeod, R Wells (R Rees, 53); J Yapp, H Bennett, C Griffiths, I Evans (J Mills, 53), L Charteris, J Merriman (D Maddocks,
5-14), R Dale, R Pugh (capt).
Tries - R Rees (2). Con - . Pens - L Thomas (3).
Referee: S Davey (England).
UEFA has today confirmed the Football Association of Wales (FAW) has been successful in its bid for the Millennium Stadium to host the 2017 UEFA Champions League Final on Saturday 3rd June, 2017 (kick-off: 19.45hrs GMT).
The winners of a filmmaking competition organised by the education charity Into Film and the WRU enjoyed a behind the scenes tour of the Millennium Stadium - and a chance to be photographed with the WRU's fire-breathing, rugby loving mascot, Scorch The Dragon, and Welsh international, Jake Ball.
The Wales Under 20 camp are in a quietly confident mood as they face Ireland in the U20 Championship, with Coaching Co-Ordinator Allan Lewis and full back Dafydd Howells targeting a top five finish in the tournament.
Wales U20 may start as favourites against Japan this evening in the U20 Championship, but Team Manager Mark Taylor is warning against complacency. He is also hoping a good win will boost morale and 'kickstart' performances.
Coach Richard Hodges is hoping Wales U20 can put a disappointing campaign behind them when they tackle Japan tomorrow as they look to finish the U20 Championship strongly to secure a good seeding for next year's tournament.