Chinese diver Wu Minxia, already a gold medalist here, had the best score Friday in preliminaries for the women's 3- meter springboard.
Wu has five Olympic medals, one short of tying countrywoman Guo Jingjing for the most ever among female divers.
She had 387.95 points Friday at the Aquatics Centre, 24.10 more than Chinese teammate He Zi, who won the synchronized springboard gold with Wu on Sunday.
Semifinals are Saturday and the finals are Sunday. China has won all four diving events so far in London after going 7-for-8 in Beijing four years ago.
Italy's Tania Cagnotto was third behind the Chinese divers and Canada's Jennifer Abel was fourth.
Americans Christina Loukas and Cassidy Krug made the semifinals. The U.S. has three diving medals at these Olympics after going since 2000 without one.