A disputed goal that had Nigeria claiming discrimination on soccer's Say No To Racism Day opened the gates for a barrage of extra-time goals by Chile at the FIFA U-20 World Cup.

After a scoreless regulation time, substitute Jaime Grondona scored six minutes into extra time and Chile piled on three more goals— two by Mauricio Isla and another by Mathias Vidangossy - in a 4-0 quarter-final route of Nigeria before 46,252 delirious fans at Olympic Stadium on Sunday.

The victory put Chile into a semifinal on Thursday in Toronto against the winner of a match later Sunday between Argentina and Mexico.

But while Chile came away relieved, the Nigerians were fuming.

English referee Howard Webb ruled there was no offside as Isla lobbed the ball over a crowd to two teammates on goalkeeper Ikechukwu Ezenwu's doorstep for a tip pass and an easy header goal by Grondona in the 96th minute of play.

As Chile rejoiced, the Nigerians mobbed Webb claiming offside, although it appeared a defender was caught out of place on an offside trap. Ezenwu was shown the yellow card for disputing the call.

When FIFA's anti-racism campaign was brought up at a post-game news conference, Nigerian coach Ladan Bosso said "What happened on the pitch, the officiating, I think FIFA has a long way to go to beat racism, because that official showed racism."

When asked if he felt Webb was a racist, Bosso said only that "It's good for FIFA to bring in the fight against racism, but they have to follow it to the letter, so the implementation will be done."

The goal forced Nigeria into all-out attack and Chile, which has yet to concede a goal in five tournament matches, took advantage.

Mathias Vidangossy was tripped in the penalty area by Suraj Sodiq, setting up the penalty shot that was converted by Isla in the 114th minute to seal the victory.

Isla got another as he went in alone and chipped the ball over the goalkeeper in the 118th and Vidangossy scored on a run down the right side in the 122nd.

"We studied Nigeria, and when they go on attack, they leave everything open at the back," said Chile coach Jose Sulantay through an interpreter. "They play long balls and rely on their speed and we were prepared for that.

"If you look at the goals, they were scored on plays."

The extra-time explosion came after an evenly played match in which Nigeria looked the stronger team at the end of regulation.

Sulantay, whose team has criss-crossed Canada twice already in the tournament, admits his team, already battling injuries, was fatigued.

"As always, there's a loser that's not happy, but we're certainly happy," he said. "We had to fight in the second half.

"The changes we made helped. We were tired, but we managed to score a goal and save things."

It is Chile's first trip to the U-20 semifinals since they hosted the tournament in 1987.

Until extra time, a crowd mostly banging drums and waving tri-coloured flags for Chile saw an even battle between the smaller, more finely skilled Chileans and a big Nigerian team that was strong on the ball.

A scoreless first half saw Chile's Nicolas Medena cut to the inside and hit a low shot that struck Ezenwa's knee and went off the bar in the 19th minute.

The Nigerians didn't exploit their clear height advantage until the 44th minute, when Chukwuma Akabueze sent a cross from the left wing that was headed off the bar by Ezekiel Bala. Until then, they had 10 mostly long shots miss the goal.

The Chileans had two glittering chances in the second half, but Ezenwa made diving saves in the 50th and 76th minutes, both on sharp, low drives by Isla.

"I felt sad when everything happened," said Bala, the Nigerian captain. "It's difficult when there's a goal and you feel like you've been cheated.

"You can't do anything about it."

Chile was hurting at forward. Striker Arturo Vidal was suspended, and Carlos Carmona, reported to have an injury, sat out the first half. While Vidal can return for the semifinals, defender Christian Sepulveda took a second yellow and will be suspended one game.

Nigeria made no changes from the starting 11 that beat Zambia in the round of 16. Nigeria was a finalist at the last U-20 World Cup in 2005 in the Netherlands.