"I trained in Austria before the worlds," said Lu. "I improved my personal best, but I am not happy with my performance. There is still a lot to improve."

Swedish Sarah Sjostrom grabbed the gold with a competition record 24.96, while Denmark's Jeanette Ottesen took the silver in 25.34.

French Olympic champion Florent Manaudou beat Nathan Adrian of United States to win the men's 50m freestyle in 21.19 seconds. Brazil's Bruno Fratus was third in 21.55.

"This is my third competition in Kazan," said the French. "Of course, I am very happy. I couldn't ask for more. It is so great that I have won gold today. I knew I would manage to swim fast but Nathan Adrian swam faster than me in the semifinal. That is why it was hard for me to win in the final. But, nevertheless, I did it!"

Australia's Emily Seebohm dominated the women's 200m back final in an Oceanian record time 2:05.81. US star Missy Franklin, London Olympic champion and world record holder of the event, settled for the silver in 2:06.34. Hungary's Katinka Hosszu timed 2:06.84 to take the bronze.

"Missy Franklin is always a tough rival, she is a running world champion," said Seebohm. "And I knew that it was going to be a tough race with her. But I was just sticking to my race plan, and that's what helped me win tonight."

South Africa also pocketed a gold medal with Chad Le Clos's 100m butterfly title. Clos timed 50.56, 0.31 seconds faster than Laszlo Cseh of Hungary, who took silver in 50.87. Singapore's Joseph Isaac Schooling broke the Asian record to finish third with 50.96. China's Li Zhuhao ranked eighth.