Marion Jones will leave Athens without an Olympic medal after she was involved in a mistake during the women's 4x100m relay final.
Jones, who ran the second leg, failed to pass the baton on to team-mate Lauryn Williams who appeared to move off her mark too soon.
The gold medal was won by Jamaica, with Russia taking the silver and the French quartet clinching the bronze.
Earlier on Friday, Jones finished fifth in the women's long jump final.
Jones said miscommunication was the reason for the United States' failure.
"I thought Angela (Williams) ran a good leg and I thought I ran a good leg," said Jones.
"I just couldn't get the baton to Lauryn, it didn't happen.
"I kept yelling, 'wait, stop, hold up' but after running 100
metres I was out of breath and I don't know if she could hear me."
Athletics legend Michael Johnson, who watched the events unfold while commentating for the BBC, was baffled by the antics of Jones and Lauryn Williams.
"I think, first and foremost, the coaches were to blame," he said.
"When they set the 'go' mark, for Williams to take off - that should be set so that Marion coming in can reach Lauryn before they get out of the zone.
"You set that mark depending on the athlete's speed.
"When they've been working on that in practice, she would come from eating a sandwich at lunch. It was from having made six attempts in the long jump."