It has been 20 years, but still a sudden runner by a star athlete remains one of the biggest unexplained sporting scandals.

When it happened on this day in 2000, emotions were running high in Australia.

Cathy Freeman in 1999. Photo: Getty

All eyes were on Cathy Freeman, an Indigenous sprinter tipped to win gold in the 400m race at the Sydney Olympic Games.

But less than 48 hours before the opening heats in her event, rival sprinter Marie-Jose Perec – a three-time Olympic champion – suddenly fled the country.

Her departure sent shockwaves around the nation and left many fans scratching their heads.

Denise Kaigler, spokeswoman for Perec’s chief sponsor, Reebok, said the star French athlete had left Australia after being accosted in Sydney at her hotel.

French athlete Marie-Jose Perec during the heats of the women’s 200m at the 1997 IAAF world athletics championships in Athens, Greece. Photo: Getty

“Marie-Jose has been under a great deal of pressure and yesterday afternoon she was harassed in her hotel room by an unidentified man who forced his way into her room and threatened her,” Ms Kaigler said.

But police and a hotel official said they had no knowledge of such an incident.

After holding out hope all day that Perec might return to the Olympics, the French team later announced that she had withdrawn from the Games.

Marie-Jose Perec (centre) won gold in the 400 metres four years earlier in 1996 at the Atlanta Olympics, with Cathy Freeman (right) in second place. Photo: Getty

“The French delegation regrets that an athlete who has brought so much to Olympism in general, and to French sports in particular, is not participating in the Sydney Games,” a statement released by the French Olympic delegation read.

The statement also said Perec’s departure had nothing to do with drug tests, and that she had not been subjected to an out-of-competition drug test before the Games.

Her last-minute escape left an indelible mark on the Sydney Olympics.

Perec was Freeman’s No.1 threat after dominating the previous Games in Atlanta in 1996, winning gold in the 200m and 400m.

Marie Jose Perec wins gold, with Cathy Freeman close behind at the 1996 Olympics in Atlanta, Georgia. Photo: Getty

At the time, Freeman had not lost the 400 metres in more than three years, but had lost seven of her nine career races against Perec.

Nicknamed ‘The Gazelle’ for her long and powerful strides, 32-year-old Perec had hoped to win an unprecedented third consecutive 400 metre gold in 2000.

But from the day she landed in Sydney, something was off.

The sports star had been a total recluse, refusing to train with the French team and hiding from reporters.

Front-page headlines of Australian newspapers following Perec’s sudden departure from the Olympic Games. Photo: Getty

To make matters worse, the media pressure intensified the more she withdrew, and she quickly became the talk of the Olympics.

Cathy Freeman celebrates after winning the women’s 400 metres at the 2000 Olympics. Photo: Getty

Perec’s only public comments before fleeing were posted on her website: “The games have hardly begun and already I wish they would end because I’m so scared,” she wrote.

“I simply have to make sure my training place stays secret. That’s the main thing, is to stay relaxed.”

To this day, no one knows why Perec gave up the chance to win her third gold medal.

Freeman, meanwhile, seized the opportunity and delivered a captivating performance, winning gold in front of a heaving stadium of supporters.

After winning the race, Freeman took a victory lap, carrying both the Aboriginal and Australian flags.

Cathy Freeman won gold in her iconic full-piece running suit. Photo: Getty