British sisters Cindy Ofili and Tiffany Porter missed out on Olympic 100m hurdles medals as the United States took a clean sweep at Rio 2016.
Favourite Brianna Rollins won in 12.48 seconds ahead of team-mates Nia Ali (12.59) and Kristi Castlin (12.61).
Ofili, 22, was in third place after the final hurdle, but was pipped by Castlin in the race for the line.
She finished fourth in a season's best 12.63, while Porter, 28, was seventh in a time of 12.76.
The sisters were both born and raised in the United States, but eligible to represent Great Britain through their London-born mother.
Porter, who had already competed for the US, switched to represent Britain in late 2010, with Ofili declaring her allegiance in 2015 after deciding to follow her sister.
Porter won bronze at the 2013 World Championships, then took Commonwealth silver a year later, but has struggled to replicate her best form this year.
Ofili has a faster time this year - 12.66 - so it was no surprise to see her push the American trio the closest.
She looked set to clinch the first major medal of her career until Castlin dipped ahead of her to take bronze by two-hundreths of a second.
'I'm proud of myself and my sister'
Cindy Ofili: "I came out here to try and get a medal for GB. It was a great race. I can only be happy with this performance. I have had an off-and-on year so I am just happy to almost get a medal."
Tiffany Porter: "I did my best. It has been a very difficult year for me but to be honest I am very proud of myself and tremendously proud of my sister. I want to succeed but I want to see my sister succeed as well."
American dream comes true
Australian defending champion Sally Pearson missed the Games after tearing her hamstring earlier this summer, paving the way for a new Olympic champion to be crowned in Rio.
An American was seen as the early favourite to succeed Pearson - but world record holder Kendra Harrison did not even qualify.
Harrison, 23, only finished sixth in the US trials, leaving 24-year-old Rollins as the fastest woman at the Games.
She controlled the race throughout as the US showed their strength in depth in the event by taking all three medals.
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