Hopes of repeating Britain's dazzling success in the pool faded today after the men and women swimmers got off to a disappointing start.
Gemma Spofforth narrowly missed out on a medal in the women's 100m backstroke, finishing a "painful" fourth just 0.04 seconds behind American Margaret Hoelzer.
The 20-year-old said: "I'm sure I will calm down and realise I finished fourth in an Olympic final, but at the moment it's just so painful to look up at that scoreboard and be so close to gold.
"It went much better than yesterday. I knew I had to go out much faster and one place I needed to improve was my turn and I think I did that."
Joanne Jackson's dreams of clinching a second Olympic medal were dashed when she failed to qualify for the 200m freestyle final.
The 21-year-old claimed a bronze in the 400 metres freestyle yesterday behind team-mate and new Olympic champion Rebecca Adlington, who took gold from American favourite Katie Hoff by just seventh hundredths of a second.
However Scotswoman Caitlin McClatchey earned herself a place in the final, finishing third in her heat behind world record holder Federica Pelligrini to qualify in seventh place in a time of 1:57.73.
In the men's 100m backstroke final, Briton Liam Tancock finished sixth as American Aaron Peirsol won the race and smashed his own world record.
Tancock, the world record holder in the 50m event, led the field at the turn with a split well inside world record pace but the early exertions caught up with the 23-year-old and he was steadily reeled in by Peirsol and the rest of the field.
Michael Phelps won his third gold medal in three days and broke his second individual world record of the Games when he obliterated the field in the final of the 200m freestyle.
His time of 1 min 42.96 secs was almost a full second under the mark he set at the world championships in Melbourne in March last year and the American was so dominant he had clear water between himself and second placed Park Tae-hwan of South Korea.
Britain's women's hockey team managed to keep their Olympic hopes alive after fighting back from 2-0 down to finish in a 2-2 draw with Argentina.