Biting opponents, racist comments — all that looked to be behind Luis Suarez, as soccer’s bad boy was maturing into a star for his club and country. Then, the old habit that most people leave behind in nursery school cropped up again in front of an audience of millions.

Faced with a smothering and frustrating Italian defense in a must-win World Cup game Tuesday, the Uruguayan superstar responded with his front teeth during a match in Natal, Brazil.

It came about the 80th minute when Suarez and Italian defender Giorgio Chiellini got tangled up in front of the Italy goal. The apparent chomp happened in an instant, but caught by television cameras, it became a worldwide sensation and could lead to Suarez being kicked out of the World Cup.

The referee didn’t see a bite, and no foul was called despite Chiellini pleading and pulling down his jersey to show a red mark on his shoulder.

About a minute later, Uruguay scored the winning goal in a 1-0 game that sent Italy home.

Uruguay will continue playing, but the federation that runs the World Cup will investigate and may suspend Suarez, who has twice before been disciplined for biting opponents in league games.

Suarez didn’t confirm or deny the bite, but said he was angry that Chiellini — one of the best defenders in the world and known for his physical play — had hit him in the eye during the game.

“These are things that happen on the pitch, we were both in the area, he thrust his shoulder into me,” Suarez said in Spanish. “These things happen on the pitch, and we don’t have to give them so much” importance.

Suarez, 27, should be celebrating a career year. After asking to be sold before the season, he stayed with Liverpool, won the scoring title and was named English Premier League’s player of the year.

Now, he’ll have to try to start rehabbing his reputation again.

Uruguay Coach Oscar Tabarez and Suarez’s teammates immediately defended their star.

“I want to say that if he’s attacked, as it has begun in this press conference, we’ll also defend him, because this is a football World Cup, not of cheap morality,” said Tabarez, who said he didn’t see a bite.

Suarez was suspended following biting incidents in the Netherlands in 2010 and in England in 2013. He also was suspended for racially abusing an opponent. British tabloids have teasingly called him a vampire, and social media artists have had fun manipulating his photo into images of Dracula and Hannibal Lecter.

And he was responsible for one of the most talked-about moments of the 2010 World Cup, when he purposefully used his hand to prevent a Ghana goal near the end of the quarterfinals. Suarez received a red card and was banned for the next game, but Ghana missed the penalty kick and was eliminated.

Uruguay defender and team captain Diego Lugano suggested Suarez was a victim of his past.

“You need to show me because I didn’t see anything. Did you see it today or did you see what happened in other years?” Lugano said. “The worst of all was Chiellini’s attitude . . . as sportsmen leaving the field, crying and appealing against a rival.”

COLOMBIA: Goalkeeper Faryd Mondragon became the oldest player to compete at a World Cup when the 43-year-old came on as a late substitute in the 4-1 win over Japan in Cuiaba, Brazil.

Mondragon entered as an 85th-minute replacement with his team ahead 3-1 to break the record set by Cameroon striker Roger Milla, who was 42 when he played in the 1994 World Cup in the United States.

CHILE: The nation’s soccer federation says it has been fined by FIFA for ticketless fans breaking through security barriers at Maracana Stadium in Rio de Janeiro.

The Chilean federation did not specify the size of the sanction in a statement on its Web site.

IVORY COAST: Coach Sabri Lamouchi will quit after his squad narrowly missed qualification with an injury-time penalty from Greece.

Lamouchi said he would not seek the renewal of his contract, which ended after the team’s matches in Brazil.

The 42-year-old former France international took over the Elephants two years ago.

— Associated Press