Nigel Carolan's youngsters sensationally defeated the defending world champions to take command of Pool A, ahead of next Wednesday's date with Georgia at the Manchester City Academy Stadium (kick-off 5.30pm).

Led by man-of-the-match James Ryan and with Andrew Porter starring in a dominant scrum, the Ireland U-20s joined the Ireland Women's team (2014) and Munster (1978) as conquerors of a Kiwi side.

Greg Jones and Adam McBurney both touched down in response to efforts from Jordie Barrett and Shaun Stevenson as the Ireland U-20s - one-point winners over Wales on Tuesday - went in at half-time leading 20-14.

The influential Bill Johnston kicked 10 points before his injury-enforced departure, and in increasingly wet conditions, Malo Tuitama's 52nd-minute try reduced the Irish advantage to 23-19.

But Ireland's set piece strength was crucial in the game's closing stages, number 8 Max Deegan scooping up possession from a wheeling five-metre scrum to gleefully dive over by the left corner flag.

The back rower's 71st-minute try was expertly converted by Johnston's replacement at out-half, Johnny McPhillips, and although Tuitama completed his brace soon after, an assured penalty strike from McPhillips - rewarding another advancing scrum - had Ireland out of reach with two minutes remaining.

Making an encouraging start to this second round tie, Shane Daly threatened on a kick chase and Hugo Keenan showed good footwork in midfield before Johnston split the posts in the third minute.

Ireland's lead lasted just three minutes, Kiwi centre Barrett's crash ball run seeing him cross just to the left of the posts and add the conversion for a 7-3 scoreline.

However, left winger Keenan gobbled up the restart and had to be hauled down ten metres short on a thrilling burst up the touchline. The Irish forwards won a scrum penalty and some terrific carries from the likes of skipper Ryan, Cillian Gallagher and McBurney preceded Johnston's second three-pointer.

Hooker McBurney's harsh sin-binning for a deliberate knock-on led to a dominant New Zealand spell. Barrett pushed an initial penalty wide but a second converted try followed in the 25th minute, Barrett releasing Stevenson to chip through on the right wing and cut inside the final defender for a very well-taken score.

Moments earlier, a kinder bounce of the ball might have seen Jacob Stockdale break clear over halfway. 14-man Ireland showed their resilience again, though, a thumping touchfinder from Johnston setting up a lineout drive that ended with flanker Jones piling over the whitewash.

Johnston's conversion closed the gap back to the minimum, with McBurney also returning to the pitch. Confidence was spreading throughout the Irish ranks and they deservedly went in front nearing the interval, the lineout providing the platform for McBurney to break free, brilliantly barge past Stevenson and dot down in the left corner.

A cracking touchline conversion was unfortunately Johnston's last meaningful act, the Clonmel native injuring his shoulder in a tackle and having to be replaced.

New Zealand came back strongly, hunting for openings, but excellent line-speed in defence from Ireland kept the title holders in check as Matthew Byrne produced a big hit on Patelesio Tomkinson and Jones did likewise on Kiwi skipper Leni Apisai, forcing a timely knock-on.

Ireland maintained a high level of physicality on the resumption, a man-and-ball tackle from centre Daly and a scrum penalty on halfway giving them another opportunity to use their effective maul.

Ulster prospect McPhillips fired over a long range penalty in heavier rain to put nine points between the sides, before TJ Va'a's deft grubber kick almost set up Stevenson for his second try of the afternoon.

The Baby Blacks were beginning to build momentum and the pressure told in the 52nd minute, a superbly-timed pass from Jordan Trainor sending winger Tuitama stepping his way through to score in the left corner. Barrett pulled the conversion wide.

Ireland's defensive workload increased up to the hour mark, New Zealand's strong bench making an impact with tall centre Barrett also threatening from a kick over the top.

Play was increasingly fractured with a slippery ball and tired bodies on both sides. Head coach Carolan reacted by making four changes in quick succession as Vincent O'Brien, debutant Vakh Abdaladze, Jimmy O'Brien and Kelvin Brown all entered the fray.

The front row reserves led the way in winning a scrum penalty on halfway, a fine boot from Stockdale giving Ireland field position after his provincial colleague McPhillips had initially missed touch.

A lineout steal from Ryan began another furious spell of carrying from the Irish eight, barnstorming loosehead Porter excelling in that regard before replacement flanker Brown was just held up by a scrambling Barrett.

Ryan then turned down a kick at the posts, opting to scrum once more following a set piece infringement five metres out. The scrum whipped around and with the ball squirting out, Deegan reacted swiftly to finish clinically in the left corner.

Ireland edged even closer to the finish line with a tremendous touchline from McPhillips, although they conceded from the restart when Jonathan Taumateine's quick tap had alarm bells ringing and he fed Tuitama for a neat finish out wide with seven minutes left.

Barrett drew the conversion wide, though, and with Ireland showing composure beyond their years, they used the scrum to work a final kickable penalty that McPhillips sent through the uprights, giving them enough of a cushion to see out the biggest result of these young players' lives.

TIME LINE:

3 minutes - Ireland penalty: Bill Johnston - 0-3;

7 mins - New Zealand try: Jordie Barrett - 5-3; conversion: Jordie Barrett - 7-3;

16 mins - Ireland penalty: Bill Johnston - 7-6;

18 mins - Ireland yellow card: Adam McBurney;

18 mins - New Zealand penalty: missed by Jordie Barrett - 7-6;

25 mins - New Zealand try: Shaun Stevenson - 12-6; conversion: Jordie Barrett - 14-6;

27 mins - Ireland try: Greg Jones - 14-11; conversion: Bill Johnston - 14-13;

34 mins - Ireland try: Adam McBurney - 14-18; conversion: Bill Johnston - 14-20;

Half-time - New Zealand 14 Ireland 20;

47 mins - Ireland penalty: Johnny McPhillips - 14-23;

52 mins - New Zealand try: Malo Tuitama - 19-23; conversion: missed by Jordie Barrett - 19-23;

71 mins - Ireland try: Max Deegan - 19-28; conversion: Johnny McPhillips - 19-30;

73 mins - New Zealand try: Malo Tuitama - 24-30; conversion: Jordie Barrett - 24-30;

78 mins - Ireland penalty: Johnny McPhillips - 24-33;

Full-time - New Zealand 24 Ireland 33

Scorers:

New Zealand: Tries: Jordie Barrett, Shaun Stevenson, Malo Tuitama 2; Cons: Jordie Barrett 2

Ireland: Tries: Greg Jones, Adam McBurney, Max Deegan; Cons: Bill Johnston 2, Johnny McPhillips; Pens: Bill Johnston 2, Johnny McPhillips 2

NEW ZEALAND U-20: Jordan Trainor (Waikato/Blues); Shaun Stevenson (Waikato/Chiefs), Patelesio Tomkinson (Otago/Highlanders), Jordie Barrett (Canterbury), Malo Tuitama (Wellington); Stephen Perofeta (Taranaki), Sam Nock (Northland/Blues); Ayden Johnstone (Waikato), Leni Apisai (Wellington/Hurricanes) (capt), Sosefo Kautai (Waikato), Quinten Strange (Tasman), Isaia Walker-Leawere (Wellington), Luke Jacobson (Waikato), Mitchell Jacobson (Waikato), Marino Mikaele-Tu'u (Hawke's Bay).

Replacements used: TJ Va’a (Wellington/Hurricanes) for Perofeta (42 mins), Jonah Lowe (Hawke’s Bay) for Tomkinson (51), Asafo Aumua (Wellington) for Apisai, Alex Fidow (Wellington) for Kautai (both 59), Sean Paranihi (Canterbury) for Johnstone (67), Hamish Dalzell (Canterbury) for Walker-Leawere (70), Jonathan Taumateine (Counties Manakau) for Nock (71). Not used: Dalton Papali'i (Auckland).

IRELAND U-20: Jacob Stockdale (Belfast Harlequins/Ulster); Matthew Byrne (Terenure College/Leinster), Shane Daly (Cork Constitution/Munster), Conor O'Brien (Clontarf/Leinster), Hugo Keenan (UCD/Leinster); Bill Johnston (Garryowen/Munster), Stephen Kerins (Sligo/Connacht); Andrew Porter (UCD/Leinster), Adam McBurney (Ballymena/Ulster), Ben Betts (Young Munster/Munster), Cillian Gallagher (Sligo/Connacht), James Ryan (Lansdowne/Leinster) (capt), Greg Jones (UCD/Leinster), David Aspil (St. Mary's College/Leinster), Max Deegan (Lansdowne/Leinster).

Replacements used: Vincent O’Brien (Cork Constitution/Munster) for Aspil (20 mins, temp sub), Jimmy O’Brien (UCD/Leinster) for C O’Brien (27-34, blood sub), Johnny McPhillips (Queen’s University/Ulster) for Johnston (37), Vakh Abdaladze (Clontarf/Leinster) for Betts, J O’Brien for C O’Brien, V O’Brien for McBurney (all 63), Kelvin Brown (Shannon/Munster) for Aspil (64), Sean O’Connor (Cashel/Munster) for Gallagher (76). Not used: James Bollard (Dublin University/Leinster), Niall Saunders (Epsom College/Exiles).

Referee: Craig Maxwell-Keys (England)