Australia's Sally Pearson grabbed some of the limelight from Usain Bolt with a World Championship record of 12.28 seconds to win the 100m hurdles in Daegu.
Pearson's time was the fastest ever at a major championships - world or Olympic - beating Americans Danielle Carruthers and Dawn Harper, who both ran personal bests.
Tiffany Porter ran a British-record 12.56 sec in the semi-final but clipped a hurdle in the final to finish out of the medals.
GB were also fourth in the women's 4x400m relay as the US won their third in a row.
Pearson was the first athlete competing in the stadium to break what has become known as the "cover curse", winning as favourite after appearing on the cover of the daily programme.
Pearson broke her own Australian record in the semi-final just 90 minutes earlier, then recorded the fourth-fastest time ever in the final.
She told BBC Sport: "My coach and I, our goal was to get a personal best in the final and after the semi-final I said to her, 'That was a personal best already, do you think I can go faster?'
"She said, 'I've been waiting for this year for a very long time and I think you can go a lot faster than that,' and so I did."
GB 4x400m relay runner Lee McConnell
“We're better than in the 2007 Worlds [when they were also fourth]. We've got four better girls here and hopefully we'll be able to lift our game in front of a home crowd in London”
Porter, who was second before hitting the penultimate barrier, told BBC Radio 5 live: "I've always said anything can happen so you just have to learn from it and move forward. I'm proud with everything so I can't be too upset."
In the relay, the US team led from the start to win in three minutes 18.09 seconds, with Jamaica second and Russia third.
Britain were led out by Perri Shakes-Drayton, with Christine Ohuruogu re-taking Ukraine on the third leg.
Despite a reshuffle to the British 4x400m relay team, which also included Nicola Sanders and Lee McConnell, they never really challenged the medal winners to finish in 3:23:63, more than four seconds behind Russia.
who was disqualified in the 400m final for false starting
, said: "It's not been a great championship for me but I'm happy I've been able to join the team. My split time is not what I expected but I'll keep running until the end of the season."
McConnell added: "We're better than in the 2007 World Championships in Osaka [when they were also fourth]. We've got four better girls here and hopefully we'll be able to lift our game in front of a home crowd in London."
The American quartet were made up of Sanya Richards-Ross, Allyson Felix, Jessica Beard, Francena McCorory, with Felix adding to her silver medal in the individual 400m and bronze in the 200m.
In the 1500m, Asbel Kiprop of Kenya won his second successive world title but got to celebrate on the top of the podium for the first time as his Berlin gold was rewarded retrospectively following a failed doping test.
Double Olympic, European and World champion Andreas Thorkildsen of Norway suffered an upset in the javelin, where a mark of 86.27m by Germany's Matthias de Zordo - with his first throw - was enough to secure gold.
Thorkildsen looked like missing out on a medal but secured silver with a fourth throw of 80.28m, well below his personal best of 91.59m.
And Croatia's Blanka Vlasic was unable to hang on to her world high jump crown as she was pipped by Anna Chicerova of Russia, the best in the world this year, who cleared 2.03m at the first attempt.