All Blacks edge Pumas but who will be next to move to No 10?

Questions come thick and fast. Are the Pumas the miracles of this rugby age? Are the All Blacks invisible to referees when they throw themselves horizontally on the ball at ruck time, contrary to the laws of the game so cherished by the international governing body? Is Ma'a Nonu the most potent inside centre – or second five-eighth, as they call it in these parts - still standing in the tournament? Does Wayne Smith, the revered New Zealand coach, still have his boots?

The answers, taken in order, are as follows: yes; apparently; almost certainly, although Jamie Roberts of Wales might have something to say on the matter; and probably not (much to the anguish of the All Black nation, who are beginning to exhaust their outside-half supplies and would not be averse to picking Smith on the bench if the No 10 from the mid-1980s felt he was up to it). A groin injury suffered by Colin Slade during yesterday's quarter-final, following hard on the heels of Daniel Carter's calamitous withdrawal from the tournament with a similar problem, has left the favourites in a very difficult place in terms of their playmaking capacity.

This might explain the fact that, for 70 minutes of a game watched by almost 58,000 spectators, the South Americans were unexpectedly close. It was only when Jerome Kaino, the excellent New Zealand flanker, finally unlocked the Argentinian defence with a high-quality pass to Kieran Read near the left touchline that the All Blacks knew for sure they would be featuring in this week's semi-final with the Wallabies. Until then, their attacking game was below-par.

Not that Nonu could have done much more to make things right. He has always been a thunderous runner, but there is so much light and shade to his game now, he can legitimately stand alongside the most creative No 12s in the sport, not merely the most destructive. But for the deep commitment of the Pumas in defence – the loose trio of Julio Farias Cabello, Juan Manuel Leguizamon and Leonardo Senatore and the marvellous lock Patricio Albacete – the Wellington centre would surely have bagged a brace of tries.

Needless to say, the Pumas captain Felipe Contepomi stood firm alongside his forwards, smashing into the All Blacks with reckless abandon despite his battered ribs. Quite how this most respected of international midfielders made such a contribution to the Pumas' campaign while in burning pain – he hurt himself in the opening game against England and has not since been able to pass or kick a ball, let alone tackle a direct opponent as powerful as Nonu, without flinching – remains a mystery.

Sadly, he was not entirely joyous as his side left the tournament, having hit their minimum target of a place in the knock-out stage. He had several long discussions with the Welsh referee Nigel Owens, generally after the Pumas had been penalised at the tackle area, and also spoke at length with the two touch judges at the final whistle. Clearly, he was exasperated at his players being treated to Owens' whistle sonata in four movements, all of them pedantic, while the All Blacks were permitted to operate in blissful silence, no matter how many players went off their feet at the breakdowns.

"I'm not allowed to talk about the officials, so I won't," Contepomi said afterward. Instead, he paid due respect to his countrymen for a display shot through with passionate intensity. "I told people in the week I wanted a proud performance," he remarked. "By that I meant that I wanted to go into the dressing room afterwards and be able to look the players in the eye, and have them look me in the eye. I'm not happy at losing by 20 points or whatever it is, but I think I can do that."

For a brief spell towards the end of the first half, the Pumas led. Behind to a couple of penalty goals kicked by the All Black scrum-half Piri Weepu, they struck back when Senatore beat Read off the base of the scrum, slipped away from Richie McCaw and made big ground into New Zealand territory. When Martin Rodriguez was hauled down just short of the line, Cabello arrived to pick up and score under the nose of Sonny Bill Williams.

Unfortunately for the Pumas, the accurate Weepu kept hurting them every time Owens took a dislike to the South American reading of the tackle-ball law and, after Read's game-busting score, the All Blacks finally warmed to their attacking game. Their second try, three minutes into stoppage-time, featured some brilliance from Williams on the left touchline – he wrenched his body this way and that to remain in play despite the attentions of three tacklers – and something similar from his fellow wing, Cory Jane, on the other side of the field. The result? A glory run for Brad Thorn, the forthright lock from Canterbury.

New Zealand still have the look of favourites about them, but this is nothing like a one-horse race. The full-back Mils Muliaina, who won his 100th cap yesterday, may be out of the tournament with a shoulder injury. "He could be in some trouble," acknowledged the head coach, Graham Henry. Just as Henry is in trouble with his options at No 10.

Scorers: New Zealand: Tries Read, Thorn; Conversion Cruden; Penalties Weepu 7. Argentina: Try Cabello; Conversion Contepomi; Penalty Bosch.

New Zealand M Muliaina (I Toeava, h-t); C Jane, C Smith, M Nonu, S B Williams; C Slade (A Cruden, 36), P Weepu (J Cowan, 78); A Woodcock, K Mealamu (A Hore, 69), O Franks (J Afoa, 80), B Thorn, S Whitelock (A Williams, 65), J Kaino, R McCaw (capt, V Vito, 78), K Read.

Argentina M Rodriguez (L Amorosino, 73); G Camacho, M Bosch, F Contepomi (capt), H Agulla (J J Imhoff, 49); S Fernandez, N Vergallo (A Lalanne, 48-52); R Roncero M Ayerza, 40+4), M Ledesma (A Creevy, 74), J Figallo (M Scelzo, 61), M Carizza (A Campos, 66), P Albacete, J F Cabello, J M Leguizamon (Lalanne, 84), L Senetore.

Referee N Owens (Wales).