RIZHAO, East China, Sept. 21 (Xinhua) -- The newly-crowned world champion Sun Yang eased to win the men`s 200 meters freestyle on the opening day of the Chinese National Swimming Championships here on Wednesday.

Sun, 800 and 1500m freestyle gold medalist at the Shanghai World championships in July, enjoyed his supremacy in the 200m free, touching home in one minute and 45.53 seconds, which could be ranked No. 6 on the world ranking so far this year. Li Yunqi of Henan came to second in 1:47.71 and Zhang Zhongchao of Shanghai had the bronze in 1:48.75.

"I have not trained systematically since the worlds. I`m happy with the results, no matter it`s good or bad. I hope I can start my steps toward the London Olympic Games through this meet," said Sun, who will also compete in the 400m, 1500m and relays for the Zhejiang team.

Meanwhile, the other two world champions Jiao Liuyang and Zhao Jing had to settle for a silver and a bronze in their events today.

Jiao, the women`s 200m butterfly world champion, showed her endurance and versatility in the 400m individual medley with a silver medal in 4:39.72. The gold medal went to Li Xuanxu of Hunan in 4:37.48.

"It was my first time to compete 400m medley. It`s much harder than my favourite 200m butterfly. I tried to make a little change this time since I compete butterfly all the time," Jiao said in smile.

Zhao, the title holder of women`s 100m backstroke in the worlds, had to settle for a third place in her trade-mark event by 0.05 seconds below Fu Yuanhui of Zhejiang in 1:00.68. Zhou Yanxin of Shanghai took the silver in 1:00.70.

"I can accept the results and the place because it is my current form. I had a rest since the world championships," Zhao said.

In other women events held on Wednesday, Zhu Jiani of Shandong claimed victory in 200m butterfly in 2:07.89, Liu Xiaoyu of Liaoning won 50m breaststroke in 31.55 and the Shanghai quartet took the gold in the 4x200m freestyle relay in 7:59.60.

In the men`s part, Chen Feiyi of Liaoning stormed in 100m backstroke in 54.42, Ma Xiang of Tianjin was fastest in the breaststroke in 1:01;33, Guangdong veteran Zhou Jiawei dominated the 100m butterfly in 52.43 and the Beijing team won the 4x100m freestyle relay in 3:20.99.

A total of 444 swimmers from 26 teams compete in the six-day Chinese national swimming championships, but Olympic champion Liu Zige, world champion Zhang Lin, Ye Shiwen and some other veterans are absent from the meet.