It is early days, but with further tricky group matches to follow against Croatia and Nigeria, one has to wonder if the collective scars from a succession of international near-misses are beginning to weigh heavily on this group. Messi also missed a penalty against Chile in the final of the 2016 Copa America and he provoked surprisingly little confidence as he stood over the ball in Russia. Halldorsson later said he was confident he knew which way Messi would shoot, even if the biggest mistake was surely in striking the ball at such a comfortable height.
Argentina's manager Jorge Sampaoli described Messi's penalty as "in the past" but conceded it had been an uncomfortable game for his talisman.
"We should have hurt our opponent more and I don't think our transitions were fast enough," he said. "We came to win against a team with a lot of people in their box that stopped us capitalising on the ball possession."
Although the final statistics showed that Argentina had 78 per cent of the ball and created more than three times Iceland's attempts on goal, that still told a skewed story.
Yes, Iceland were physical and hard-working but they also played with an attacking intent that troubled Argentina. Indeed, after two early Messi free kicks were almost turned in by Nicolas Otamendi and then Nicolas Tagliafico, Iceland missed two wonderful opportunities.
First Alfred Finnbogason crossed for Gyfli Sigurdsson, whose effort was saved by Willy Caballero, then Birkir Bjarnason shot wide when he should have punished a poor clearance by the Chelsea goalkeeper. It appeared that Argentina's cast of attacking talent would punish such profligacy when Sergio Aguero brilliantly controlled a powerful Marcos Rojo pass before shooting beyond Halldorsson.
It was crucial that Iceland responded quickly and another mistake by Caballero helped them draw level within four minutes. Gylfi Sigurdsson had crossed and, with Caballero and right back Eduardo Salvio both missing chances to clear, Finnbogason marked Iceland's first World Cup match with a goal to enter their football folklore.
Sampaoli was happier with Argentina's performance thereafter but, with the team so built around Messi and his radar deserting him, they rarely looked likely to fashion an equaliser elsewhere.
Once Cristian Pavon had replaced Angel di Maria, Argentina certainly looked more effective. Yet Iceland never ceased working and deserved yet another famous result.
Questioned about celebrating a draw as if they had won, they were rightly unapologetic. "Are you Cristiano Ronaldo's uncle?" asked Halldorsson. "We were playing against one of the best teams in the world, against the best player in the world, in our first World Cup. It was exactly the same as in the Euros. We celebrated a point against Cristiano Ronaldo as we did against Messi. We know how important every point is to get out of the group."
Argentina 1
Iceland 1
Denmark 1
Peru 0
Croatia 2
Nigeria 0
