Nicole Cooke's hopes of a cycling medal disappeared once again when she could only finish a disappointing 19th in the women's individual time trial.
Cooke, who was fifth in Sunday's road race, confirmed afterwards that she will not compete in the track events.
Holland's Leontien Zijlaard-Van Moorsel, who crashed in the road race, successfully defended her time crown.
American Deirdre Demet-Barry took the silver 24.09 seconds back, with Swiss cyclist Karin Thuerig winning bronze.
Zijlaard-Van Moorsel was the third last rider out on the course but had to wait until the last two riders times were known before she could celebrate victory.
But the Dutchwoman, whose body still showed the bruises from her fall on Sunday, admitted she was far from fully fit going into the race
"I have pain everywhere and it was getting worse as the race went on," she said.
"After about 10 kilometres I started to get a bad headache.
"I did have my doubts about competing last Sunday but I got a good night's sleep and on Monday morning I thought to myself that I didn't want my career to end that way, with a crash."
Zijlaard-Van Moorsel is among the favourites to win a second gold in the track individual pursuit on Saturday.