In this undated file photo, Zhang Yufei of China competes during women's 200m butterfly final of swimming at the 18th Asian Games in Jakarta, Indonesia. Zhang won the gold medal. (YUE YUEWEI / XINHUA)

QINGDAO, China - Asian record holder Zhang Yufei clocked 55.96 seconds in the women's 100m butterfly heat on the first day of the Chinese National Swimming Championships here on Friday, nabbing the No 1 spot in the current world rankings.

Zhang smashed 25.82 split in the first 50m and 55.96 at the wall, 0.34 shy of her own Asian record.

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Asian record holder Zhang Yufei smashed 25.82 split in the first 50m and 55.96 at the wall, 0.34 shy of her own Asian record

"I am not happy with the time as I planned to break the world record of 55.48 in the heats. I hope to add my name with the new world record before the Olympic Games, then I won't be too nervous," said Zhang, also a member of the world record setting team in the mixed 4X100m medley relay.

"With the Olympic Games coming soon, I feel more and more nervous. I try to relax myself by watching TV series and play musical instruments, like the piano," said the 23-year-old.

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More than 500 swimmers from 26 teams are competing in the nine-day championships, which also serves as one of the Tokyo 2020 Olympic trials.