By David McDaid
BBC Olympic sports reporter in Los Angeles
Britain's Sophie Thornhill beat team-mate Lora Fachie to tandem pursuit gold on day one of the Para-cycling Track World Championships in Los Angeles.
It was a fifth world title for the Rio tandem kilo gold medallist, 21, piloted by Corrine Hall.
The pair finished more than five seconds clear of Fachie, who was riding with Hazel McLeod.
Paralympic triathlon silver medallist Alison Patrick just missed out on a medal on her international track debut.
Patrick, who won silver with McLeod in Rio, lost out to Belgium by more than seven seconds with pilot Helen Scott in the ride-off for bronze while Aileen McGlynn and Louise Haston were sixth.
The event in America is vital for visually-impaired athletes hoping to gain qualification points towards the 2018 Commonwealth Games in Australia.
Riders, including 14-time Paralympic gold medallist Sarah Storey, had been critical of the UCI for the short build-up to the event.
"Considering the event was only announced seven weeks ago, its amazing we're standing on top of the podium," Thornhill told BBC Sport.
Fachie, who married team-mate Neil Fachie last year, added: "I couldn't make it to Glasgow 2014 so I'm hoping to do enough here to get selected for Gold Coast."
On Friday, Jody Cundy goes in the C4 kilometre time trial, with Jon Gildea competing in the C5 class.UCI 'making 'mockery' of Para-cycling World Championships