China seized its first-ever men's gold for swimming in World Championships on Wednesday, with Zhang Lin improving Grant Hackett's four-year-old 800 meters freestyle world record by more than six seconds.

Zhang sliced six-and-a-half seconds off the previous world record of 7:38.65, set by Hackett at the 2005 World Championships in Montreal.

Tunisia's Ous Mellouli, overtaken by Zhang at 200m mark, picked up the silver in 7:35.27 and Canadian Ryan Cochrane was third in 7:41.92.

I'm more than five seconds quicker than Hackett's record and I'm still surprised, Zhang said. I can't believe it.

It was the 22-year-old's first gold medal at the World Championships - and China's first ever men's swimming gold at a major international event.

Throughout the whole day yesterday, Zhang's swim was replayed on China Central Television's sports channel, while Internet news sites were awash with his achievements. Some netizens even called him China's new sports icon after Liu Xiang.

Five years ago at the Athens Games, Liu Xiang became China's first Olympic sprinter champion by winning the 110-meter hurdles and Asia's first male athlete to crown the event.

Now in Rome, Zhang's achievement not only boosts his confidence in the coming men's 1500-meter freestyle race, but also makes China's swimmers hopeful of more surprises in London 2012.

China's men's swimming has always been regarded as the country's weakest event, lacking competitive edge at the world's major events.

Even in Asia, China's men's swimming has for a long time lagged behind Japan and Korea. Before the Rome championships, the best results achieved were Zeng Qiliang's 100-meter breaststroke and Wu Peng's 200-meter butterfly silvers at the world championships in 1998 and 2007 respectively.

Swimming pools, alongside the track and field, have always been the most important battlefields in the Olympic Games for competing nations, with many medals produced from the two arenas.

However, during the Beijing Games last year, China failed to win a gold in track and field and only won one gold in the women's 200-meter butterfly. Zhang Lin's silver in the men's 400-meter freestyle was already their best ever Olympic mark and China's first ever medal in men's swimming.

Zhang's breakthrough at the Beijing Olympic Games largely came from his unique way of training compared with other Chinese swimmers.

In late 2007, he went to Australia to train under Denis Cotterell, the former coach of Australian swimming great Hackett, becoming the first Chinese swimmer allowed to train outside the country.

Under the instruction of Cotterell, Zhang has been making extraordinary progress, especially in 2009, winning three gold medals in the 200-meter, 400-meter and 1500-meter freestyle in the Short Course Open in Japan in February.

In the National Championships in April, Zhang was on even better form, winning the three events in this year's world's best results.

I've been under great pressure before the final, I didn't even know how to swim, Zhang wrote in his blog afterward. My Olympic silver and the gold here are of the same importance, showing our improvements.