The Great Britain and United States teams both crashed out of the Olympic 4x100m men's relay in the heats after botching their baton handovers.
Craig Pickering set off too soon for his leg for GB's defending champions, and the handover with Marlon Devonish took place outside the permitted area.
Earlier, a disastrous handover between Darvis Patton and Tyson Gay cost the US their hopes of reaching the final.
The US women's relay team repeated the mistake, but the GB women went through.
In wet conditions inside the Bird's Nest Stadium, the changeover between the US women's team's Torri Edwards and Lauren Williams went badly wrong.
606: DEBATE
Great Britain's men went into the race as defending champions after edging out the US in the final strides in Athens.
But any hopes of a repeat of that success were ended in abrupt fashion as Pickering and Devonish got their timings wrong.
Pickering was clearly upset after the incident, and accepted his share of the responsibility straight away.
"I'm so disappointed in myself - I'm sorry," said Pickering.
"I feel like I've let the team down and the country down. Unfortunately for the next four years I am going to be remembered as the guy who messed up.
"It's not been a great Olympics for me, and it's a shame because I think we've got a really good team - especially with the US going out."
But the experienced Devonish offered his support to the 21-year-old.
"Craig should not take full responsibility for that," he said.
"It's a team event. We trained really hard for this and anything can happen."
The other two members of the GB men's relay team were Tyrone Edgar and Simeon Williamson.
For the US men's team, the news was just as bad and Gay said he had been at fault.
"I don't know what happened," said Gay.
"(Patton) said the stick was in my hand. I think I felt it, but it wasn't in all the way before I grabbed it. I take the blame for it. It was my fault."
~RS~q~RS~~RS~z~RS~21~RS~)