Saint Lucia's Alfred wins superb 100 metres gold

Alfred, 23, made her usual slick start and remained clear in heavy rain to come home in a national record 10.72 seconds.

World champion and race favourite Sha'Carri Richardson took silver in 10.87 but the American never really threatened and her compatriot Melissa Jefferson claimed bronze in 10.92.

Double Olympic champion Fraser-Pryce, appearing in her fifth Olympics, was listed as 'Did Not Start' shortly before the semi-finals and her lane remained empty.

Social media footage later emerged of her and Jamaican team members arguing with officials who appeared to be refusing to let her in. Richardson was also seen waiting at the same gate.

Fraser-Pryce was heard saying "they've changed the rules, we always come through this gate".

However, Jamaican Chef de Mission Ian Kelly said her absence was due to injury.

"There was an issue but that was not the reason she did not run," he told Reuters.

"Mrs Fraser-Pryce was allowed to enter the warm-up track but from another gate from which she was directed to enter from. There is no truth that she was not allowed to enter the stadium. Unfortunately she was not able to compete due to an injury sustained during her final warm-up."

With Fraser-Pryce missing the semi-final, Richardson was slow out of the blocks and could not overhaul Alfred.

It was almost a repeat of last year's world championships, when Richardson sneaked into the final as a fast loser and won the title from lane nine.

There was to be no repeat this time, however, as U.S.-based Alfred hit her stride brilliantly and splashed home for a glorious gold.

Alfred broke down in tears as she dedicated her win to her late father.

"He believed that I could do it. He passed away in 2013 - now he couldn't get to see me on the biggest stage of my career," she told reporters. "He believed that I could be an Olympian.

"Growing up I used to be on the field, struggling with no shoes, running barefoot, running in my school uniform.

"We barely had facilities. I'm really hoping this gold medal helps the youth and helps St Lucian government to also build the new stadium to just keep the sport growing."

The result meant the United States' 28-year gold medal drought in the event goes on. Gail Devers was their last winner in 1996. Marion Jones was stripped of her 2000 Olympic gold for doping.

It also ended Jamaica's stranglehold on the women's 100m after they won the last four Olympic golds and 10 of the 12 available medals.

Their only finalist on Saturday was 19-year-old Tia Clayton, who was an impressive winner of her semi-final in 10.89 but managed only 11.04 in the final to finish seventh.