ROSTOV-ON-DON, Russia — Mexico's biggest worry at the World Cup may be its fans instead of its next opponent, struggling South Korea.

The Mexican football federation was fined 10,000 Swiss francs ($10,000) and warned of further sanctions over a chant by supporters considered to be homophobic during the opening game against Germany. Fans in Mexico use the chant to insult opposing goalkeepers as they take a goal kick. Widely considered a slur, some argue there is no discriminatory intent.

As travelling Mexican fans prepare to descend on this southern Russian city, players and the federation are imploring them not to repeat it at Saturday's match, in messages on television and social media. The Group F game will be attended by South Korean President Moon Jae-in.

"For the Mexican fan, the World Cup is a party. You can see it on the street the whole time. But at the stadium, fans should stop the chant, or modify it, or change it all together. It would be better for everyone," Mexican federation general secretary Guillermo Cantu said.

FIFA had warned the federation, he said, that supporters identified as chanting the slur could have their Fan IDs cancelled.

"The rules have been there since the tournament started, so in the end, it's our responsibility."

The team arrived in Rostov late Thursday and was greeted by a small group of fans outside their hotel.

The Mexicans have reached the last 16 in their six previous World Cups, and are on course to make it seven after beating Germany 1-0. Javier Hernandez tore past defenders and found Hirving Lozano for a stylish goal in the 35th minute.

Coach Juan Carlos Osorio is a fan of reshuffling his lineup — a tactic inspired by former Manchester United manager Alex Ferguson — but is likely to stick to many of his opening game starters, relying on his back four to stop the pacey Koreans.

Celebrations in Mexico City of the goal against Germany were so rowdy that seismologists checked reports of an artificial earthquake. It was eventually ruled out.

But Mexico midfielder Marco Fabian was one of several players who warned against complacency.

"We reached our first target and have beaten Germany, but we can't sit back," Fabian said. "Some consider us to be group favourites now, and that's a compliment — but it's one we shouldn't believe. There are no favourites in this World Cup."

The Koreans, stung by their 1-0 defeat by Sweden, could reconsider their attacking 4-3-3 formation that provided little threat and handed space to their opponents.

Midfielder Koo Ja-cheol, who plays at Bundesliga club Augsburg, said players were studying Mexico on their tablets and had identified Hernandez as the major threat.

"Of course we are not ready to give up. Everyone put in so much effort to get here," Koo said. "What we want is to turn fans' disappointment into joy."

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Rodriguez reported from Moscow. Follow Gatopoulos at http://www.twitter.com/dgatopoulos and Rodriguez at http://www.twitter.com/@crodriguezap

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