There were boos from their own fans at half-time, a remarkable late save from goalkeeper Raul Rangel and plenty of last-ditch defending, but Mexico got the job done.The World Cup co-hosts sealed a 1-0 win and their place in the knockouts with a 50th-minute goal from Luis Romo, which also ensured they claim top spot in Group A.Romo’s effort came after a goalkeeping howler from Kim Seung-gyu, who fumbled a catch before the midfielder poked home.Aside from a Raul Jimenez shot that Kim then saved smartly in the 75th minute and an Obed Vargas stinger repelled by the South Korea ‘keeper, this looked to be an uninspiring affair — until that late save from Rangel, denying Cho Gue-sung on the line, above.Mexico became the first team to qualify from the group stage and now have a round-of-32 game in Mexico City on the horizon.Here, Jacob Whitehead and Matt Slater analyse the key talking points.Did the save of the tournament rescue Mexico?Not one, not two, but three. South Korea were in the last chance saloon of Mexico’s Ranch Country, firing a last-gasp cross towards goal in their attempts to equalise.Rushing in on goal, Cho directed his header well, low and powerfully onto the goalline of the near post. Chivas goalkeeper Rangel, playing in front of his home fans at the Estadio Akron, somehow threw himself down to save it — only for the ball to rebound, looping, back towards the net.Sat on his backside, players sprinting in, Rangel was the calmest man in the stadium; the one still point amid the madness. His right arm prevented a certain goal — before somehow catching the ball while riding a thump from the onrushing Oh Hyeon-gyu.