Jose Ramirez has failed in his bid to become the first American since Oscar de la Hoya in 1992 to win an Olympic Games lightweight gold medal.
The teenager lost to Uzbekistan’s Fazliddin Gaibnazarov in London on Thursday night.
Ramirez was the favourite but a slow start saw the 19-year-old fall too far behind. Not even a superb final round, which he won 6-3, could redress the balance. He lost 11-15.
He became the sixth American to lose in London after the team had started so promisingly with four victories in the first series of bouts.
Ramirez, who has been linked, along with team-mate and fellow 19-year-old Joseph Diaz to De la Hoya's Golden Boy stable, was disappointed but said he took some positives from the fight.
"The one thing I got from this is that it has opened new doors for me," he said.
"Yeah it is a little disappointing. We came up short as we are a young and hungry team," said Ramirez, who has considered going to university before turning professional.
TAYLOR IN TEARS
The London Games also ended in tears for lightweight Ross Taylor as he became the first Briton to be eliminated. He lost to Italy's Domenico Valentino.
The 21-year-old Scot was unable to find a solution against his experienced opponent, the 2009 world champion, losing 10-15 in their second-round bout.
Taylor was inconsolable after the fight. "I'm incredibly disappointed after all the hard work to get here," Taylor said. "I just couldn't deliver the win this evening.
"I have enjoyed the build-up and I am grateful for all the support I have received. I will now reflect on what happened."
The former British taekwondo champion, has no intention of turning professional yet.
"I intend to fight at the 2014 Commonwealth Games in Glasgow and go one better than I did in Dalhi in 2010 to win gold."
Valentino said he got a wake-up call from his corner men going into the third round with just a one-point advantage, 8-7.