Luis Romo settled this encounter with a single strike five minutes into the second half, and Mexico did not need anything more. One goal, one clean sheet, six points from six: Javier Aguirre's side are through Group A in perfect shape, having not conceded a single goal in two outings at Estadio Akron.
The match had the texture of a cup tie more than a free-flowing group-stage encounter. Mexico, despite holding only 43 per cent of the ball, were the more purposeful side in the moments that counted. South Korea moved it briskly enough, finishing with 567 passes at 84 per cent accuracy, but precision in their own half did not translate into genuine menace. Six offsides told part of the story; two shots on target in 94 minutes told the rest.
For all their possession, Myung-Bo Hong's side could not find a way past Raúl Rangel, who was called upon for three saves and made each one without fuss. The goalkeeper's positioning was assured throughout, and Mexico's backline gave him precious little to worry about outside those moments. Edson Álvarez, deployed in defence rather than his more familiar midfield role, was the anchor of the unit, reading the game well and rarely needing to do anything hurried.
The Romo goal arrived at exactly the right time for the hosts. South Korea had grown into the first half without ever truly threatening, and the temptation was to imagine the second period might follow the same shape. Instead, Mexico struck early in it. Romo, the midfield man whose energy had been a constant irritant to the Korean press, found space and converted to make it 1-0. It was the only goal the game required.
From there, Mexico managed the match with a composure that borders on the professional in its most complimentary sense. Brian Gutiérrez and Romo came off in the 71st minute having done their jobs, replaced by Orbelín Pineda and Obed Vargas, both of whom helped the home side keep the game at arm's length through the closing stages. Roberto Alvarado and Raúl Jiménez were withdrawn in the 80th minute, and while neither had been particularly explosive in front of goal, both had worked the channels and made Korea's wide defenders work.
Son Heung-min, the most celebrated name on the pitch, had a quiet evening by his own high standards. He and Jae-sung Lee were both replaced at the hour mark as Hong sought fresh legs and a different angle of attack, sending on Hwang Hee-chan and Hyeon-gyu Oh. Neither substitute altered the picture. Ji-sung Eom, on for the final 23 minutes, at least offered energy and was the brightest of the Korean bench contributions, but the deficit was never genuinely threatened.
Kang-in Lee and Seung Ho Paik collected yellow cards, adding a hint of frustration to South Korea's afternoon. Neither dismissal changed the match, but both reflected the mounting tension of a side that could see the game slipping from them without quite knowing how to retrieve it.
Mexico's expected goals figure of 0.48 against South Korea's 0.63 is a curious statistical footnote to a game the hosts controlled in feel if not in possession. Aguirre set his team up to be compact and direct, and the plan worked exactly as drawn. With three points already banked from Matchday One, Mexico arrived here already in reasonable shape; they leave it as group winners with a game to spare.
South Korea, on three points, remain very much alive. They face a sharper test if they intend to advance, and Myung-Bo Hong will know the performance here was not enough, whatever the shape of what comes next. The numbers flattered them. The scoreboard did not.