However, as the match entered added-on time, Messi strode forward before curling the ball into the top corner from 25 yards to earn his team a place in the second round.
Read below to see how the action unfolded in Belo Horizonte.
4.01pmHello, and welcome to Sports Mole's coverage of the match between Argentina and Iran at the World Cup finals.
4.04pmI'm sure that everyone is awaiting the time in the tournament where the some of the elite teams go head-to-head, but for some nations, it's all about occasions like this one in Belo Horizonte. Iran will never go to a World Cup finals with any ambition of winning the tournament, but they will relish the opportunity of facing some of the best players in the world. They may not possess the same quality as their opponents today, but Messi, Aguero, Di Maria - be prepared for a gutsy effort from Iran.
4.06pmThat said, the gulf in class between the two teams is huge. Some bookmakers have Argentina as 1/10 to win today, which, for a World Cup finals, is a rare occurrence.
4.08pmWithout further ado, let's crack on with the team news.
4.11pmARGENTINA XI: Romero; Zabaleta, Garay, F. Fernandez, Rojo; Gago, Mascherano, Di Maria; Higuain, Messi, Aguero
4.12pmIRAN XI: Haghighi, Haji Safi, Hosseini, Sadeghi, Nekounam, Shojaei, Timotian, Montarezi, Ghooc'd, Dejagah, Pooladi
4.14pmIf anyone thought that Argentina coach Alejandro Sabella might rest a few players for today's game, think again. Sabella starts with the team that started the second half against Bosnia-Herzegovina, which means that Fernando Gago and Gonzalo Higuain have been included after previously featuring on the bench.
4.18pmAs for Iran, they include the three players that will probably be familiar to English fans, with Fulham's Ashkan Dejagah, Charlton Athletic's Reza Ghoochannejhad and former Bolton Wanderers midfielder Andranik Teymourian taking their place against their superior counterparts.
4.22pmAs you will probably already know, there are two more games to follow this one. At 8pm (BST), Germany will look to build on their win over Portugal with a similar result against Ghana, while Saturday's final fixture sees Nigeria go up against Bosnia-Herzegovina. As always, you can follow both matches with Sports Mole.
4.26pmArgentina entered this tournament as one of the favourites to lift the Jules Rimet trophy, but they looked anything but against Bosnia in their first fixture. Despite taking the lead through an own goal, they looked slow and methodical against a well-oiled Bosnian outfit, but once Sabella changed from a 3-5-2 to 4-3-3 formation, the South American team began to show their class, as did Lionel Messi who scored a terrific goal from the edge of the area.
4.29pmIran got their tournament off to a solid start with a goalless draw against Nigeria. It was far from pretty, but when you have only won one of your previous nine World Cup games, a point to kick things off isn't such a bad thing.
4.33pmGoing back to that last stat, the fact that Iran have only ever won one match at a World Cup finals tells you everything that you need to know about the size of their task. In contrast, Argentina have won 38 from 71 matches, scoring 125 goals in the process.
4.36pmFootage has emerged today of clashes between Brazil and Argentina supporters in Belo Horizonte. Let's hope the match goes off without incident - like in Argentina's first match, I expect there to be a Brazilian presence inside the stadium.
4.40pmAfter just looking back at Argentina's record at the last five World Cups, I realised that they haven't reached the last four in any of those competitions. For such a big footballing nation, that's really poor, and there will be huge disappoint back in Buenos Aries and the rest of Argentina if their heroes can't improve on that record in Brazil.
4.43pmAfter the results in Group E last night, it's looking as though Argentina will play either Ecuador or Switzerland in the second, providing that they can secure four points from their final two games. In theory, they look like certainties to make the latter stages, but we've already in this competition that surprises can happen.
4.47pmThere are less than 15 minutes until kickoff in Belo Horizonte, so I think that it's time for a prediction. Guess which way I'm going to go...
4.50pmPREDICTION! Argentina will win this game. Simple as. It's just trying to predict by how many. I'm going to say 4-0, because once they establish a lead, I think that Alejandro Sabella will begin to ring the changes.
4.53pmThe two teams are beginning to congregate in the tunnel. Imagine being an Iran player right now? You'd be tempted to ask Lionel Messi for his autograph, wouldn't you? If they ask nicely, someone might get his shirt at full time.
4.56pmIt's a pro Argentina crowd in Belo Horizonte, but you knew that already. The Argentine supporters are belting out their national anthem. It's quite the sight and the sound.
1 minIran get us underway.
2 minThe Iranian players aren't backing out of any challenges. A couple of Argentina players have already hit the deck, and Angel di Maria is receiving treatment.
5 minCHANCE! Iran win a free kick in a threatening position on the left-hand side after a handball by Pablo Zabaleta. It's a terrific ball in from Ashkan Dejagah, but Jalal Hosseini can't divert his header on target. That was a chance.
6 minUp the other end, Pablo Zabaleta is released into an attacking position, but after trying to play in Sergio Aguero, the Manchester City striker's attempt to turn and shoot was thwarted by the Iranian backline.
10 minWe are 10 minutes through this match, and Iran are doing a fine job so far. Goalkeeper Alireza Haghighi hasn't had anything to deal with as of yet. There's a long way to go though...
12 minHere comes the pressure. Angel di Maria and Lionel Messi come alive in the final third, but Iran manage to get bodies in the way before a shot can reach Haghighi's goal. Argentina retrieve the ball back on the halfway line, but after a patient buildup, the ball goes behind for a goal kick.
13 minCHANCE! Fernando Gago plays a superb through ball to the onrushing Gonzalo Higuain, but when he reaches the ball, he is too close to Haghighi and the Iranian stopper manages to block the shot. However, he's took an almighty whack on his knee and is currently receiving treatment. He looks like he is going to be fine though.
17 minIran put together a string of passes on the right flank, and after taking control of the ball in the corner, they manage to win a set piece. The ball into the box is a good one, but Federico Fernandez rises highest to head away.
19 minSHOT! The ball rebounds into the path of Angel di Maria, who is waiting on the edge of the penalty area, but despite his best attempts to whip his foot around the ball, he can't keep it down and his strike clears the bar by a couple of yards.
22 minCHANCE! Argentina are warming to the task now. A ball is fired into Gonzalo Higuain, who flicks the ball into the path of Sergio Aguero but the attacker's first-time strike from 14 yards is well tipped away by Alireza Haghighi.
25 minCHANCE! From the corner, Marcos Rojo jumps above the Iranian defence to power a header on goal but it evades the corner by a matter of inches. Moments later, Sergio Aguero is involved in an incident which sees the corner flag unearthed, but he fails to put it back in, forcing the referee to jog half the length of the pitch to restore it to its usual spot. It's all a bit silly...
30 minWe reach the 30-minute mark and we are still goalless. It's a bit of a surprise, but Iran are competing well and deserve to be level. However, they are beginning to drop deeper and deeper, and they aren't going to survive it they continue doing so.
32 minArgentina win a free from 25 yards out, and it's central. This is Messi territory.
33 minFalse alarm. The Barcelona maestro steps up with plenty of intent but his curling effort was never threatening the goal. The Argentina supporters let out a sigh of frustration, but I don't think it was as big as Iran's sigh of relief.
36 minArgentina win another set piece around the Iran penalty area, but this time, it's on the left-hand side. It looks more like a crossing opportunity for Messi rather than a strike on goal.
37 minCHANCE! Argentina are getting closer. Messi provides a superb delivery for Ezequiel Garay at the back post, but the Benfica man can only head over from six yards.
41 minAs we move closer to the half-time whistle, Iran are putting nine men behind the ball and it's forcing Argentina to put more thought into their buildup play. Five minutes to go to the break. It would be an excellent achievement if Iran can get to half time without conceding.
42 minCHANCE! Forget holding out until the break - Iran should be ahead! What an opportunity for Jalal Hosseini. A corner was swung in from the right by Ashkan Dejagah for the defender to beat his marker and send a bullet header towards goal. Unfortunately, it cleared the crossbar by inches.
45 minThere will be two minutes of added-on time.
45+2 minNow then, Iran win another free kick on the left-hand side. This will be the final chance before half time.
45+3 minAshkan Dejagah's set pieces have been brilliant, and another ball into the ball is scrambled away by Argentina. The ball falls to Ehsan Hajsafi, but he drives his 30-yard effort over the crossbar. That's half time.
45+3 minHALF TIME: Argentina 0-0 Iran
5.50pmSo then, what do you make of that? Argentina's performance in that first half was much better in comparison to that of their opening 45 minutes against Bosnia-Herzegovina, but they have been frustrated by Iran, who fully deserve to get to half time still on level terms. We could be in for some second half!
5.55pmArgentine had 78% of possession and 10 shots during that first half, but they couldn't get the ball past Alireza Haghighi. In truth, the Iran stopper hasn't had that many saves to make, but Argentina have been a whisker away from finding the corner on a number of occasions.
5.58pmDespite their frustration, I think that Alejandro Sabella will bide his time before contemplating any changes. He has players that he can turn to, but one goal could potentially open the floodgates.
46 minArgentina get us back underway. Expect a fast start from La Albiceleste.
47 minArgentina win an early corner after pressure from Gonzalo Higuain but it comes to nothing. Sabella's side seem content to probe for now.
50 minSHOT! Lionel Messi breaks forward with speed before laying the ball off to Pablo Zabaleta. The full-back cut inside onto his left foot before firing well wide of the far post. The Manchester City man should have done better from there.
53 minCHANCE! Oh my. That was terrific. Iran break forward from the back before getting the ball out to the right. The inswinging cross managed to find Reza Ghoochannejhad, who got ahead of Zabaleta to head on target but Sergio Romero managed to parry the ball away.
54 minPENALTY APPEAL! Ashkan Dejagah thinks that he should be given a penalty after beating Pablo Zabaleta to the ball, but the referee waves his claims away. It's a stone-waller! Dejagah is furious, and understandably so.
57 minFor now, let's just forget about me saying that Argentina would win this game. It's far from a certainty!
60 minCHANCE! Iran survive, but only just! Lionel Messi picks up the ball on the halfway line before driving towards the Iran defence. The former world player of the year decides to go it alone, but he just misses the far corner with a curler from 20 yards.
62 minTalk about determination. Andranik Teymourian bulldozes his way through challenges with Messi and Fernando Gago before earning a free kick. Fans of Bolton and Fulham will be wandering where that kind of desire was when he was playing in England!
65 minI tell you something, Argentina are living so dangerously. After Ehsan Hajsafi's strike is deflected wide, the resulting corner sees Argentine defenders on the floor trying to block a tap in in the six-yard box. They survive on this occasion, but Iran are well up for this.
67 minCHANCE! Unbelievable! Ashkan Dejagah thinks he has scored with a diving header after getting in front of Pablo Zabaleta, but Sergio Romero pulls off an incredible one-handed save to turn the ball over for a corner. What a match, what an occasion!
70 min20 minutes to go, and this match could go either way. I never, ever thought I'd be saying that. There will be statues of Carlos Queiroz back in Iran if he can pull this one off.
72 minBOOKING! Iran's Masoud Shojaei goes into the book for a late challenge on Angel di Maria. Lionel Messi takes responsibility for the free kick, but although his effort momentarily looks to be heading towards goal, it hits the side-netting.
75 minMoments later, Di Maria fires a shot straight at Alireza Haghighi from 10 yards. Rodrigo Palacio and Ezequiel Lavezzi are replacing Sergio Aguero and Gonzalo Higuain.
79 minArgentina are upping the tempo, but they are seeing a number of balls into the box easily cleared by Iran. Like in the first half, Iran are dropping deeper and deeper, but they need to push up. They are capable of scoring against this Argentina defence.
82 minEzequiel Lavezzi skilfully works his way down the right before winning a corner. The resulting set piece causes plenty of panic inside the Iran penalty area but they manage to survive. Eight minutes to go.
85 minCHANCE! A sublime diagonal ball finds Rodrigo Palacio around 12 yards out, but his header is directed towards the near post rather than the far one, and Alireza Haghighi is able to pull off a comfortable save.
87 minCHANCE! Sergio Romero saves Argentina again! Alireza Jahanbakhsh, who has replaced Ashkan Dejagah, storms down the left before playing a through ball to Reza Ghoochannejhad, who takes a touch before firing the ball towards the far corner, only for Romero to stick out two hands to push the ball away.
90 minThere will be four minutes of added-on time.
90+1 minGOAL! Argentina 1-0 Iran (Messi)
90+1 minA goal that makes the airs on the back of your net stand up. It's gut-wrenching for Iran, but what a stunning goal from Lionel Messi. The Barcelona man took control of the ball 30 yards out before advancing towards the edge of the area and curling the ball into the top corner. I feel so sorry for Iran, but that was Messi at his very best.
90+4 minI don't know what to say after that. I think a part of me must be Iranian because I'm gutted for them. We are into the final minute of added-on time.
90+4 minFULL TIME: Argentina 1-0 Iran
6.56pmIt's all over in Belo Horizonte and Argentina have somehow managed to come away with three points against the most inspired performances that you could ever imagine from Iran. Lionel Messi will be the name on the back pages, but Iran deserve so much credit for their efforts.
6.57pmWhen Messi picked up the ball, there was an inevitability about the way he strode forward and fired the ball into the top corner. It was sheer class. No goalkeeper in the world would have save that shot.
7.00pmBefore I leave you, a final word on Iran. From back to front, they were incredible. The defence as a whole produced the perfect display, and the front players ran themselves into the ground. They aren't out of the tournament just yet, but they were minutes away from something magical this evening and they had it taken away from them by a genius.
7.04pmThat's it from Sports Mole for this match. Thank you for joining us for one of the most enjoyable matches of the tournament so far. Goodbye for now.