Puerto Ricos Jasmine Camacho-Quinn opened her Olympic 100 metres hurdles title defence by posting the fastest time in the heats on Wednesday, as all the favourites moved onto the semi-finals.
Nigerias world record holder Tobi Amusan and American Masai Russell are among those trying to knock her off the throne, while home hope Cyrena Samba-Mayela is among Frances brightest hopes for an individual track gold.
Camacho-Quinn showed she was in no mood to let that happen, though, as she glided over the barriers to finish in 12.42 seconds, three-tenths clear of Britains Cindy Sember.
The first three in each heat and the next fastest three across all the races moved on.
I just had to talk to myself, get myself ready. I knew what I was capable of, so I just wanted to go out there and enjoy myself, Camacho-Quinn told reporters.
