In the end it wasn't the individual skills of the host team that ended the Irish challenge at the 10th World Youth Championships. What beat the Irish at the Sani Abacha stadium here in Kano was the combination Brian Kerr predicted would cause his side the greatest difficulties. Heat and physical strength.

Nigeria clinched their place in the quarter-finals in a penalty shoot-out, but the fact that they got themselves back on level terms, after Richard Sadlier had given Ireland a 35th-minute lead with a close-range strike, had everything to do with the fact that they jumped that little bit higher and pressed that little bit harder.

And the afternoon heat of their homeland ensured that, as the Irish struggled through the second half, they could do both for longer.

After a first period in which the Irish more than matched the efforts of their opponents, the second half turned in a five-minute spell midway through the half during which the Chinese referee, rather than either of the teams, dominated the proceedings.

When, after 68 minutes, Gary Doherty pushed the ball past Chikelue Iloanuse only to be taken down as he scurried goal-wards, Lu Jun looked to have little option but to send off the Nigerian, who was the last man back. Remarkably, he didn't even show a yellow card. When the Irish bench became agitated at his restraint, the official incensed the Irish bench further by ordering team coach Noel O'Reilly out of the dug-out and into the stand.

Distracted from the job in hand, Ireland promptly conceded an equaliser, with Pius Ikedia capitalising on confusion in the defence to slip a shot between Barry Quinn, Thomas Heary and Barry Ferguson which reached the top right-hand corner, despite Jason Gavin's attempt to intercept it on the line.

The timing of the goal was an enormous bonus for Nigeria. Inside the stadium all but the 100 Irish supporters amongst the capacity 15,000 crowd had been willing the home team forward. However, the host's fans turned on their Flying Eagles on each of the previous occasions they failed to win in this competition and in a country where the supporters are inclined to throw urine-filled bottles at home teams who disappoint, there was a sense that 14,900 flies were about to be undone when Ikedia struck.

Suddenly, Nigeria appeared to be holding all of the cards. They were now enjoying the lion's share of possession and, consequently, creating the bulk of the game's chances. For Ireland, Quinn and Stephen McPhail still attempted to pull the strings in midfield, but too many of their team-mates' legs were tiring.

Ikedia might have edged his side in front when he drove against the post from the right-hand side of the area, while Eddy Dombraye headed against it minutes later. On both occasions Ireland's defence, in which Jason Gavin was again outstanding, reacted quickly enough to clear the danger from the rebounds.

At the other end, the chances were a good deal more scarce. Damien Duff, clearly exhausted, was replaced by Richie Baker with 12 minutes to play. Robbie Keane fared little better than his senior international team-mate and faced some tight and aggressive marking. In fact, the discipline shown by a Nigeria side more accustomed to throwing everything forward was admirable.

The 5-2-3 formation they employed could hardly have been described as negative, but it undoubtedly represented a more balanced approach than they had adopted under their previous coach. The relentless work of John Aranka on Duff and Ozuah Ikemefuna on Keane contributed much to their side's victory.

Still they mightn't have won if the Wolves striker had been awarded the penalty he deserved midway though extra-time, or if, just after extra-time started, he had put away the sort of header that normally would have been considered a certainty to hit the net.

Drombaye had a clear-cut chance to put Nigeria through on the golden goal rule, too, but he blasted over from six yards out.

With the sides still deadlocked after 120 minutes, it came down to penalties. Having won last year's European title with spot-kicks, that didn't seem like too unfavourable a development for Kerr's players. After Ger Crossley and Paul Donnolly twice drew their side level in the shoot-out, however, Thomas Heary hit his shot too close to the goalkeeper who saved with his legs.

The hosts, meanwhile, converted all five of their attempts, so Barry Quinn's successful effort wasn't enough to even require Keane to take Ireland's fifth.

Republic Of Ireland: Delaney (Everton); Donnolly (Leeds), Gavin (Middlesbrough), Ferguson (Coventry), Heary (Huddersfield); Healy (Celtic), Quinn (Coventry), McPhail (Leeds), Duff (Blackburn); Sadlier (Millwall), Keane (Wolves).

Subs: Doherty (Luton) for Sadlier (65 mins), Baker (Shelbourne) for Duff (78 mins), Crossley (Celtic) for Healy (90 mins).

Nigeria: Okoye; Iloanusi; Aranka, Afolabi, Ikemefuna, Melkam; Okunowo, Musa; Ikedia, Yobo, Garba. Subs: Dombraye for Yobo (66 mins), Shittu for Musa (86 mins), Okpala for Melkam (118 mins).

Referee: Lu Jun (China).