Fellow Australian Lauren Reynolds then finished fifth in the final on Friday, her best result at three Olympics, as British rider Bethany Shriever and Niek Kimmann of The Netherlands won the gold medals.
Sakakibara’s older brother Kai was also on the way to riding at the Olympics in BMX when he crashed at a World Cup in February last year and suffered a traumatic brain injury.
He is in Tokyo with his mother and grandmother to be part of the Paralympic torch relay, but was not at the track on Friday because of COVID-19 restrictions.
The cruel nature of BMX racing was on full display at Ariake Urban Sports Park, with Sakakibara among several top riders who crashed out of medal contention.
American star Alise Willoughby, the wife of Australia’s London silver medallist Sam, crashed with Sakakibara and also did not make the final.
Connor Fields, the American gold medallist in Rio, crashed in the semis and reportedly was rushed to hospital.
Like Sakakibara, he was stretchered off the track, but the Australian was soon back on her feet.
Sakakibara was in tears as she nursed a torn jersey sleeve and a bandage on her right arm.
The Australian Olympic Committee reported she showed signs of a mild concussion, but was medically cleared after 30 minutes.
“It just really sucks and I can’t believe it’s over,” she told the Seven Network.
“It’s just so disappointing, I feel like I let everyone down, especially my brother.”
Sakakibara had just lost the lead in the third semi-final race to American Alise Willoughby when they crashed out.
“Unfortunately I got cut off by Alise,” Sakakibara said.
In the women’s final, Reynolds made a solid start, but was soon caught out of position and was never in the medal hunt.
It was the first time the 30-year-old had made the Olympic final.
“I gave it everything I had, I got a little bit squished going into that first corner, it’s almost game over,” she said.
“I’m proud of my efforts, that’s for sure – I’m hungry and I want more.”
Reynolds added she felt for Sakakibara and Willoughby.
“It’s a brutal sport, it’s a battle we’re in out there,” she said.
“Alisa and Saya were some of the best at it, they weren’t in the mix.”
Shriever edged out Colombian legend Mariana Pajon, with Dutch rider Merel Smulders taking bronze.
Kimman won the men’s gold after suffering a knee injury only a few days ago, when he collided with an official while training on the BMX track.
Kye White of Great Britain won silver and then celebrated with Shriever after her winning ride, while Carlos Ramirez of Colombia was third.
Australian Anthony Dean did not qualify for the men’s semis.
Friday’s schedule was put back by 45 minutes because of concerns about lightning and conditions were overcast, with some light rain.
Sakakibara had a bad first race in the semis, but won her second round and was in the box seat to reach the finals when she crashed.
She later vowed to race at the 2024 Paris Olympics.Jump to next article