There’s no debate that Lionel Messi is having the tournament of his life. Aged 39, at likely his final World Cup, he continues to win matches on his own.With 78 minutes on the clock and Argentina 2-0 down against Egypt, they were staring at a round-of-16 exit and a meek defence of their crown. At which point, enter Messi.The captain made the first goal, headed home by Cristian Romero, and then scored the second four minutes later, before Enzo Fernandez headed in the winner in stoppage time — the latest a team has successfully staged a comeback win this big inside 90 minutes in tournament history.In the previous round, Argentina also won 3-2 after an engrossing game, twice being pegged back by Cape Verde, the tournament’s surprise package. Two outswinging Messi corners in extra time led to two goals. This was after the Inter Miami forward had put them 1-0 up mid-way through the first half after some clever movement. He walked back slowly from an offside position to avoid being marked, then sprinted forward to latch onto Lisandro Martinez’s ball over the top, taking one touch to control and another to score.Argentina’s results make for good reading: 12 straight wins and, in the four-year cycle since winning the 2022 World Cup in Qatar, just four defeats.That includes the 2024 Copa America, also hosted in the United States, which they won by conceding just once in six matches. Such continental success is significant given they were on a 25-year drought when head coach Lionel Scaloni took charge in 2018.Then, in 2021, he led Messi and Argentina to the Copa America title, beating fierce rivals Brazil in Rio de Janeiro. Now they have back-to-back titles after previously having been serial losers of finals, and are just three wins away from back-to-back World Cup trophies. Messi, with eight goals, is leading the golden boot race, one away from France’s Kylian Mbappe and Norway’s Erling Haaland.So, what’s there to be concerned about?Well, they are starting to see some flaws exposed. A lack of athleticism in midfield showed when Egypt counter-attacked in Atlanta. Julian Alvarez helplessly tried to trigger a counter-press when Martinez lost the ball by the corner flag — he’d been boxed in two-vs-one.Haissem Hassan, Egypt’s right midfielder, threatened with dribbles all match, and carried the ball into the final third past Fernandez. He gave it to Mohamed Salah, who split two defenders to find Mostafa Ziko. The striker chipped Emiliano Martinez, and, momentarily, Egypt were 2-0 up, before VAR controversially disallowed it for a foul early in the move.Nine minutes later, it happened again. A Messi inswinging corner was headed clear and, somehow, Salah found himself in space, leading a counter-attack. Leandro Paredes made a recovery run but mistimed his tackle, and the ball was worked to Hassan on the edge of the box.The overload — four-vs-three — was in Argentina’s favour, though they stood off Hassan too much and he hit the byline again. This opened up a cutback for Ziko, who ghosted in to fire a second past Martinez. There was no problem with that one.The comeback owed to Argentina doing something they did less than everyone else in the group stage: crossing. Scaloni’s side attempted 26 crosses in total and 18 in open play against Egypt, the latter their most in a major tournament game under the 48-year-old.This is a team without wingers, save for Thiago Almada.“He gives us a little more one-vs-one (quality),” Scaloni told reporters during the group stage. “Before, there were four midfielders… which was much more about play and footwork.”Almada is the closest player in profile to Angel Di Maria, the 38-year-old former Real Madrid and Manchester United winger who scored in the last World Cup final but has since retired from international duty.So the crossing burden, like all others, falls to Messi. He picked out Romero, a centre-back playing emergency striker, to make it 2-1.The equaliser was much scrappier. Messi had two goes at the inswinging cross. Mohanad Lasheen blocked the first and then deflected the second, which sent it looping towards the back post. Lautaro Martinez hooked it centrally, where Gonzalo Montiel set up Messi for a half-volley.Argentina’s reliance on Messi, and desire to be unstoppable rather than unpredictable, may bring future problems.The shape is a narrow 4-4-2 to overload the centre with No 10s rather than wingers. Scaloni wants to make passing lanes through midfield so Messi can receive to feet, or for his side to counter-press when moves break down.Often the midfield resembles a box, especially in the deep build-up. Messi has licence to roam. Egypt disrupted this with good man-marking in central midfield, and had centre-back Rami Rabia step to Messi when defending in a mid-block.Flying full-backs provide the width. That came from left-back Nicolas Tagliafico against Egypt.Egypt pressed Argentina high and defended in a 4-4-2 — sometimes dropping to a 6-2-2 by bringing their wingers down.Tagliafico’s forward dashes almost brought two first-half goals. He ran onto Paredes’ long ball and hit a low ball to Alvarez, who forced an excellent save from Mostafa Shobeir.A similar move led to the Argentina penalty. Messi dropped deep, split the Egypt midfield to find Fernandez, and the Chelsea man threaded a through ball for Tagliafico, who was bundled over by Hassan.Messi, for the second time this tournament (and fourth in total from eight World Cup penalties), failed to convert from the spot. Shobeir dived low to his left and parried the effort away. Scaloni’s simplest decision is to put Alexis Mac Allister or Fernandez on penalties instead.Compare Scaloni’s side to France, the losing finalists from 2022, and they have fewer open-play solutions, beyond giving the ball to Messi. They even owed their 3-1 win against Jordan in the final group-stage match to direct free-kick goals from their star man and Giovani Lo Celso, plus a Lautaro penalty.Eight of the teams who had been left in the round of 16 have made more final-third regains than Argentina, while they rank second for tackles — a sign of defending much more reactively than proactively. They rarely press to conserve Messi’s energy, and he bemoaned how Cape Verde played through their gaps when Argentina tried to smother them.For Scaloni to be reduced to tears in an on-pitch interview after the Egypt win, completely overwhelmed by the late comeback, was telling.Their Messi-orientated tactics are working, but cracks are starting to show.