The tacos that Son Heung-min ate were reportedly of the Al Pastor and Arrachera variety. The former Tottenham forward was mobbed after taking an Uber from South Korea’s training camp, perhaps the most-talked about base at this World Cup tournament, to downtown Guadalajara. The crowds were another signal, if any were needed, of the forward’s global popularity, though the online advice was that he should have gone to a better restaurant.

And he could do with better service too, as demonstrated by the 1-0 defeat against Mexico in the second game of Group A. The forward, who turns 34 before the quarter-final stage, was feeding off scraps as the Taegeuk Warriors played passively for a draw until a big error from Kim Seung-gyu – the goalkeeper was another taco muncher – gave the co‑hosts a goal from nowhere and a first place in the round of 32. For Korea, facing South Africa in the final game, a win would be great, a draw would be enough for second but defeat would mean either the lottery of third place or even a slip into fourth and guaranteed elimination.

Son lasted less than an hour before being subbed off. In the first game, he missed chances and was replaced after 69 minutes as South Korea came back from a goal down to beat Czechia 2-1. Playing in a central role does not seem to be working, as has often been the case. One of the debates back home is whether the forward should be on the left with Oh Hyeon-gyu, who replaced Son in the opener to score the winner and has been in good form for Besiktas, starting.

The game against South Africa, who have yet to impress, in Monterrey is obviously a big one. If Son, helped by the head coach, Hong Myung-bo, can burst into life and lead the team to victory then all will enter the knockout stages in good shape. A draw would suffice in what is far from the toughest group but it could mean the uncertain mood around the team continues.

When Asia’s most successful World Cup side touched down in Mexico, where they and their fans have been treated royally by the locals, recent form had been patchy and expectations were low. But the opening win against Czechia was an impressive and exciting performance, though tempered with the obvious caveat that after two games Czechia look to be the weakest of the European contingent.

Still, it was an encouraging start – though soon overshadowed by other events. Son’s powers on the pitch are naturally not what they were a few years ago but he is still the centre of attention off it. During a training session on 7 June as the players ran around the pitch, a member of the media was overheard on camera mocking Son’s military service record. The Los Angeles FC forward earned exemption from the 21-month period of service mandatory for all non-disabled males by winning gold at the 2018 Asian Games, though still had to carry out basic training in 2020.

In response to the leaked footage, the Korea Football Association issued a statement expressing regret over “inappropriate remarks made by some media personnel … the recent leak of inappropriate conversations between some media officials at a training site caused great shock and disappointment to the team”.

For a while the team refused to talk to domestic media as the issue of military service made its way to Mexico. The millions of men who undertake the full duty – and society as a whole – do not take kindly to the rich and/or famous dodging their duty and there have been many examples of this.

Son, and other players, have done nothing wrong but there have been surveys that suggest public support for allowing sports stars to avoid full service is fading. BTS (hugely popular in Mexico to the extent that the president, Claudia Sheinbaum, asked her Korean counterpart, Lee Jae Myung, to persuade the boyband to add more tour dates in the country) had to take a break for a couple of years and reported for duty. The occasional remark about players getting off easily may not seem to be anything to get too excited about, at least for those on the outside, but the whole issue is a complex and sensitive one for Koreans.

Talking of the military, the Mexican one shot down a drone hovering about another Korea training session before the game with the hosts. That went badly with South Korea showing little of the attacking verve that had impressed against Czechia. Now there is some pressure.

Another consequence of the result is that Mexico are through. The co-hosts at full strength and needing something would surely be too strong for Czechia, but now the European team have a chance of a win. That would mean that if Korea lost against South Africa then it would probably be all over. What a disaster that would be. What all fans, players and media want is a win to get the confidence flowing and the focus back on football, entry to the US and the opportunity for more restaurant trips.