Reigning Asian Games champion Chen Zuo from China said he will keep challenging his own limit.

China's Chen Zuo celebrates after winning the men's 100m freestyle swimming finals at the 15th Asian Games in Doha December 6, 2006. Chen set a new Asian record of 49.06 seconds. [Reuters]

The defending champion powered to the victory in men's 100m freestyle in an Asian record time of 49.06 seconds here on Wednesday in the Asian Games, beating his previous Asian mark by half second.

"To tell the truth, I had expected to break the record before the race, so I am very happy with the result," said the 24-year- old Chen. "I will keep challenging my own limit in the future."

Chen, having to settle with two silver medals in 4x100m and 4x200m free relay while Japan claimed golds in both events, led the field all the way before powering to the finish.

"In the relay event yesterday, although my team only had a silver, my personal result was not bad which gave me a lot of confidence today," he said.

"I changed my strategy tonight. I used to speed up after the 50m mark but in Doha I kept a fast pace from the very beginning and it turned out to be a good idea," he said.

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In Tuesday's 4x100m free relay, Chen clocked 48.73, faster than his Chinese teammates and any other swimmer in this event.

Chinese head coach Zhang Yadong heaped praised for Chen.

"He did a great job by improving his personal best by 0.5. He was the first Asian swimmer to break into 50 in 100m free and his result today put him just outside the 49 barrier," said Zhang.

"Besides, he will have a good place in the world rankings as there was never before a Chinese male swimmer standing in the top 20," he said.

Chen will be in the 12th place in the world rankings with the result.

South Korea's golden boy Park Tae Hwan was pushed to the second in 55.02 after taking the 200m and 400m free titles. Daisuke Hosokawa, anchor of the 4x100m winning team of Japan, was third in 50.25.