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).
Wales Head Coach Rob Howley talks to WRU TV's Sebastian Barrett about the 36-man squad he has just named for the forthcoming Under Armour series, which includes two uncapped players, Ospreys duo Sam Davies and Rory Thornton.
Head coach Rowland Phillips is deligthed he can now call BT Sport Cardiff Arms Park home for his Wales Women's side, who launch their international season next month with games against Scotland and UK Armed Forces in the heart of the capital city.
Wales Sevens star Sam Cross has put his home town club of Brynmawr on the map after winning a silver medal at the Rio Olympics with Team GB. His club have now honoured him by naming their players bar after him, as WRU TV discovered at the official launch, recently.
One of the newest members of the Principality Premiership, Bargoed admit it's proving to be a steep learning curve at the highest level, but are determined to become a force to be reckoned with. WRU TV visited the club last weekend when they took on Llanelli.
Table-topping Aberavon travel to north Wales to tackle RGC 1404 as both teams defend unbeaten starts to the season in the Principality Premiership. WRU TV's Graeme Gillespie visited the Wizards to see how their preparations were going for the game of the weekend.
The Half a Game initiative is currently sweeping across Wales and proving a major success. The scheme aims to give every young player at least half a game every weekend. WRU TV recently visited a festival in Narberth where clubs have fully embraced the initiative.
Both Bargoed and Swansea were seeking their first win of the Principality Premiership season this afternoon. It proved a fruitful day for the hosts - not only did they win, but Bargoed claimed a try bonus point.