Britain's Hannah Miley could not make the podium as Ye Shiwen of China broke the world record to win 400m individual medley gold in London.
The Scot, 22, finished fifth and must now focus on the 200m medley.
Ye, 16, set a new world best of four minutes 28.43 seconds, ahead of American world champion Elizabeth Beisel and fellow Chinese Li Xuanxu.
Miley told BBC Sport: "Apologies if anyone had high expectations of me. I gave it everything I had."
Ye broke the previous record of 4:29.45, set by Australia's Stephanie Rice at the 2008 Beijing Games.
After she won silver at last year's World Championships, there had been high hopes that Miley could get on the podium, but the pace was too strong and she never threatened for a medal.
"It was probably just down to the heats," added Miley, who had finished sixth on Saturday morning to qualify for the final.
"They were the fastest that have ever been recorded in the history of the 400m IM and the challenge was who can recover the fastest to be able to put out again - and the young ones won.
"I feel really privileged that I could be in the same water as a world record holder. I said from the start I can only control myself and I'm afraid I can't control what anyone else does.
"For me, it was an honest effort and I apologise to anyone who feels disappointed in me, but I feel really proud and happy to have been able to represent Britain and the crowd were absolutely awesome."
Elsewhere, Ellen Gandy qualified for the 100m butterfly final, but team-mate Fran Halsall missed out, as did Michael Jamieson and Craig Benson in the 100m breaststroke semi-final.
David Carry finished seventh in the 400m freestyle final, and the British women's 4x100m sprint freestyle squad came a creditable fifth.