Mexico City, Mexico

Shakira had the spectators out of their seats at the World Cup opening ceremony Thursday, but outside the Estadio Azteca fans and protesters clashed with police.

A crush to get into an overcrowded fan zone in the centre of Mexico City and protests near the stadium made for a chaotic day that contrasted with the festive atmosphere inside the Azteca.

The venerable and now renovated stadium in the Mexican capital was a fitting venue for the tournament curtainraiser between co-hosts Mexico and South Africa, having staged the World Cup finals in 1970 and 1986.

Colombian pop superstar Shakira, who herself is a veteran of past World Cups, lit up the stadium by partnering with Nigerian Burna Boy to perform "Dai Dai", the official song of the tournament, bringing roars from the 80,000-strong crowd.

Dancers twirled around a giant model of the World Cup trophy while fireworks streaked across the pitch as the noise levels ramped up.

"It's already a party in Mexico," Ingrid Orozco, a 40-year-old supporter, told AFP.

"It's amazing," said Gustavo Ramirez, 19.

That noise got louder as Mexico charged to a dramatic 2-0 win over the overwhelmed South Africans, who had two players sent off.

- 'Stop pushing' -

But in the centre of Mexico City, thousands of fans pushed and shoved as they attempted to enter the official World Cup fan zone to watch the game.

Access to the area in Zocalo plaza was hampered by metal barriers erected in recent days to prevent protesting teachers reaching the area.

"Stop pushing and shoving, there are children here, you're like animals!" a city official shouted through a megaphone as he tried to control access to the venue where the opening game was shown on a giant screen.

Some fans threw water bottles and hurled insults at police as well as chanting in support of the Mexican team.

"It took us an hour to get in, it was chaos, and getting out was even worse," 49-year-old Victor Gomez told AFP, who, along with his partner gave up on watching the match at that venue.

"Inside, you can't even walk, and you can't see anything; we could only get access to the very last little screen over here."

The local government announced on social media that the site was "full" and urged fans to go to other sites.

President Claudia Sheinbaum had been expected to watch the game at the fan zone but instead took in the action from a local sports center following days of protests in the area by the teachers, who are demanding pay rises.

The teachers, joined by relatives of Mexicans who have gone missing, and student activists gathered early Thursday outside the stadium.

As the match began some protesters breached barriers and exchanged blows with officers guarding the stadium's perimeter.

A handful of youths smashed vehicle windows with bats as police fired tear gas and dispatched mounted officers to corral the protesters, who scattered on foot.

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